The 4 holes are 2.5 inches wide by 1.062 inches high. Would that suit the plate you speak of? Are these plates available anywhere? The holes are drilled and not deburred on the back, looks like they may have been drilled in a hurry or somewhat careless. Any ideas?
Thanks for the replies, I think I'll just leave the holes just in case I come across one of those plates. Heck, maybe I'll just make a brass plate stating the year and model just for fun.