It's a standard 70's aluminum slot wheel. They were made by probably half a dozen different companies. Craigar, AR, Weld, to name a few. You'd see them on everything from Fiats to Chevys to Mustangs. Very common, heavy, unbalanced, cheap. Never came on Fiats as OEM. Some added on by dealers but mostly aftermarket guys. Very Rock n Roll, not likely to find any today though.
Joe's info is correct, nearly every wheel mfg made those slot mags in the 70's. Not too many imports sported them, but they were the wheel of the day for Detroit iron. I happen to have a set of them on my 69 Spider