This link should help.
http://www.toyotaownersclub.com/forums/topic/11619-chassis-numbers-mk1-2-3/
 

Hi Locked On, everything Dudeman has said so far is correct.
Just to help clarify (I own an import too), most of the information you require can be translated from the factory VIN plate.
Don't worry about the "6F91mportthxa7042" plate, all Japanese domestic market cars simply had the chassis stamped there (in your case it should be SW20-0010853 underneath), the plate would have been added at some stage during compliance.
 
So to translate the factory VIN plate:
MODEL:     SW20  = MR2 2nd Generation
                 AJMZZ = J for T-Bar Roof
                 MZZ for GT/GT-S Type
ENGINE:     3S-GTE = Toyota S Series engine, wide-angle valve, electronic fuel injection Turbo
CC:            engine displacement in cubic centimetres
Frame No:   the frame/chassis number
Color:         202 = Toyota paint code/black
Trans:         E153 = transmission used in turbo models for the MR2
 
The best way to tell the build date for our cars is to look at the frame number, in your case it's SW20-0010853.
The SW20 went through 5 revisions, with the first revision being produced between 12/1989 to 11/1991 and having a frame number between 0000001 and 0059265.
As you can see yours was from the earlier run, further checks show it has a March 1990 build date (reference: http://www.toyodiy.com/parts/q?vin=SW20-0010853).
 
As the GT-S model was not introduced until December 91, your car should be a GT model before the revision 2 updates.
The leather seats also help identify it as a GT as the GT-S came with cloth seats, however this may not be as useful (for identifying models) as previous owners may have swapped them in.
 
Hope this helps clarify things.
 
Cheers

Wow!! this forum is such a goldmine of information.

Thats some awesome info, I'm going to go home and check my VIN tonight just for shiz and giggles

Other than the Toyota factory VIN plate, there are actually many visual ques that can help identify where your car came from too.
Some of the lesser known ones I’ve found over the years are Japanese cars having a narrower number plate slot front and rear and two flare holder hooks on the passenger side foot well.
I have every Japanese mr2 brochure from 1984 to 2006 so if you have any questions on model differences I should be able to help :)

I have to bend the Victorian number plate (and now the historic number plate) to fit into the JDM rear bar. Pretty sure that makes it unroadworthy but it mustn't be checked often as it has passed 3 times with bent plates.

Deevon
I have to bend the Victorian number plate (and now the historic number plate) to fit into the JDM rear bar. Pretty sure that makes it unroadworthy but it mustn't be checked often as it has passed 3 times with bent plates.

 
Doubt it would be unroadworthy as fresh imports need to be complied how they are, and when doing pinks it would mean every silvia/skyline owner would fail on the spot lol. 

Yeah I've never really pushed the point to be honest but I have a mate who is a cop and he reckons it'd be unroadworthy for the simple reason of a road side camera has to have clear vision of the plates, so you're not allowed to modify them at all.
 
But, that's just one guy, I wasn't going to argue to the point haha.

https://www.vicroads.vic.gov.au/registration/number-plates/display-of-number-plates
 
"If your vehicle makes it difficult for you to meet these requirements, you need to make them as closely as possible. "
 
Looks like he was wrong

Deevon
https://www.vicroads.vic.gov.au/registration/number-plates/display-of-number-plates
 
"If your vehicle makes it difficult for you to meet these requirements, you need to make them as closely as possible. "
 
Looks like he was wrong

 
No, he was right.  The rest of that link also says, "Number plates must be clearly visible from 20m at all points in the shaded areas marked "A".

'Must' is the word you need to obey, if you have bent them into a JDM slot and it can be seen/read by everyones favourite cameras and people you probably wouldn't have a problem, but if you have bent an angle great enough so they can't you're in the book. 
 
It also says - for people who may read, "You need to make them as closely as possible" as "Oh I can make my own" - this, "Unauthorised number plates
Displaying number plates that haven't been issued by VicRoads on a vehicle is an offence under the Road Safety (Vehicles) Regulations (except for 'home-made' plates on exempt trailers). This includes the illegal re-manafacturing of existing number plates issued by VicRoads in a different format, style or material" 
 
In NSW you can't bend a plate at all to fit, they call it, "Defacing the plate" 
 
People can always bring up examples where they went through an RBT site X amount of times and the police didn't say anything about the plates - but one day you'll have the pleasure of meeting a highway patrol/traffic cop who really knows the legislation, takes their job very seriously, doesn't have a sense of humour - and spots you out for a cruise in your garage queen. He yanks the plates off your car, gives you a stinging fine and loss of points - and then says as you don't have plates on your car anymore you can't drive it home and must have it towed. Then your breakdown service refuses to tow you as you haven't broken down but have committed on offence! Then the day really sucks.
 
So if you have a JDM bumper and don't live in a state where they make plates that fit i'd suggest you make some brackets to sit behind the plates so they can be nice and flat and seen by our friendly authorities. As I always go on about, keep your car nice and compliant with road regs, give the ticket writers less to write about for when that day does come - like I kept saying to a member here "Get rid of those blue LED's - you'll get fined" (he did eventually - fined, not rid of them…) some absolute traffic nazi goes all Rommel on your car...