A/C compressor compatibility

HI there.
I understand an ST184r has Denso A/C compressor CM1755. Mine has just failed.
 
I understand an ST204 has Denso compressor CM1638, which I can get from a private seller.
 
The CM1638 has the 4-pin plug at the front bottom which goes to the speed censor just like the CM1755, and the two units look fairly similar, however I would like to know if the CM1638 can replace a CM1755 for an ST184r.
 
Any help will be appreciated.