Did the GTAs come with offset center caps or is this an aftermarket thing? Depending on who you ask I've been getting two different answers so I'll just have a democratic solution. Whichever gets the most votes is the one I'm gonna say is right. I ask because I'm gonna get some 87 center caps and I'm not sure which ones to go with.

 

They're the same for all diamond spoke wheels, the medalion that goes on them changes tho. The 2nd gen snowflake and 3rd gen formula center caps are the same size/design as the GTAs too, but in colours other than black.

 

They are all not the same. Classic Industries and a couple other places sell a 16mm offset center cap.