The hinge tab that is bolted to the grill is tapered from Ford and squared from Willys. Look for a script F on the bucket between where the wire exits it and the mounting. Or, just look at the BOTTOM of the bucket near the bezel for a drain hole that Ford buckets have and Willys buckets DON'T have.
GPW 17963 4/24/42 Chester, PA. USA 20113232 (est.)
GPW 85976 12/9/42 Louisville, KY. USA unknown
GPW 108552 4/21/43 Louisville, KY. USA 20371278
Bantam T3 4582 10/29/42 USA 0173499 (est.)