Uuhhhh..... I'm gonna go on a limb and say "Porsche"
Kiddin.
Check the inside of the wheel for a stamp with the diameter, width and lip markings.
EG: 18x8J 18" wheel, 8" diameter, "J" lip, or roughly something along those lines.
Right around that mark should be a stamp from the manufacturer. I know the old wheels were made by Fuchs and had a fox head stamp IIRC, and some others by BBS. Those I have no idea, but look somewhat RUF-esque if I didn't know any better... which I don't.
the second one to think there ruf wheels .. i think there oz wheels the by the bolt face (its rounded) ....no making on the inside at all........... i build bbs wheels for a hobby so im preety good at figuring out makers.. im a wheel hoor..