It definitely is an ARC plug 'n play for the MKI, as I compared it to pics I have of some, but it is also definitely a bit beat up. If they are not supplied, you will need to fabricate some L-brackets to connect the intercooler to the oem body spots, where the bolts are sticking out of the intercooler.
FYI: the ARC may be cool to have as they are definitely a bit rare, but consider this, they have only 12 cross sections, as compared to about 18 on the oem unit. While the ARC is definitely a thicker core, I'm not 100% sure that the thicker core and fewer cross sections can make up for the loss of about 6 cross sections on the oem unit, even though the oem unit is a bit thinner. Just something to think about.