the easiest way i could tell between my OEM rims and replicas was the center caps did't fit perfectly on the replicas, they do not flush up with the rim. Mine and my buddies both sat about a 1/8th of a inch in. With the OEMs the center caps will fit flush.
Thats weird you mentioned the center cap, only one of my aftermarket 10.5's Do that.
If you have a good eye, you can tell just by looking at them. The chrome plating on the aftermarket rims will me a little wavey unlike the fasctory ones youll have on the from.
That or look for the pealing on the inside of the rim, lol.
You can tell by the inside of the rim...it has a wavy chrome finish on the inside of the wheel...not really visible...center caps are loose but I fixed mine with some scotch tape on the inside!
mine aren't chrome, but the center caps fit fine and flush. the only way i was really able to tell on mine were because the clear finish on the replica's had just the slightest tinge of yellow while the stockers were just the slightest blueish. you really can't tell, I had to stare at them for a long time. i did work in a paint dept for over 5 years so you kind of develop an eye for this thing too.