telling difference of 1g/2gcams

[BKs50trimGST]

i'm just wondering how do you tell the difference between 1g stock cams and stock 2g cams? i know that 1g cams are a little bigger height wise, like 1/10 an inch or something, but i was wondering about the letters that are on the cams. like 2g cams have a J,J for the letters. and i heard that 1g cams have A,C, and J depending on the year. I looked on old forums and couldn't find anything, so if anyone knows it'll help me out, thanks