'87 325i wheel/center cap question, please help

[edge33]

Recently purchased an '87 325i convertible. Trying to figure out what wheel center cap goes on the wheels but it looks like the centers are different between the front and rear wheels. I think the previous owner might have had custom/after market wheels (wheels came with mismatched lugs, unnecessary wheel spacers on front wheels only) and then threw these back on but they are missing the center cap emblems. I ordered oem center cap emblems but can't figure out how they would attach. Any advice for an idiot is much appreciated. Pictures of wheels and new center caps here http://imgur.com/gallery/Hlfp1ff

[Critter7r]

They just snap into the center. Those look to be BMW factory wheels, so the caps should fit. But it looks like the retaining lip on the wheel was ground off of at least one of them, so maybe not.