Okay, So im pretty sure im going to answer my own question here but here it goes.
ive got a set of brand new 2020 17" steel rims and a set of *unsure of what year" 17" steel rims. All of the numbers on the rims are the same but the numbers after DOT.. Im guessing the numbers after the DOT are the manufacture and year? for example -J17X6J DOT 3 20 - im guessing this means March 2020 manufacture?
also, after the DOT 3 20 it has the following - /6M7 27CT . What do these numbers and letters mean? does the 27CT mean 27 to centre? therefore a 27+ offset?
Im sure non of this makes sense, so ill upload some photos of both rims.
Any help would be great.