Headlights if original might be the best indicator as they are unique. I'd have to look in my old car bible to try to pin it down. Web sites mostly show cars that have been modified with head light buckets from Dietz or King Bee. Could be a Chrysler product, but not Plymouth as they started in '28, but there are dozens of manufacturers who made cars only for 2 to 5 years and then went belly up..