Thanks for the ideas.
Mike - Google shows me that 1951 Missouri truck plates must be as rare as hen's teeth. I can find nothing. I haven't tried the DMV route yet. They are less than helpful most of the time.
Kevin - I agree that a 1992 plate is far from antique. That reminds me of the time I saw an early 90's Mazda Miata running around with Historic Vehicle plates.
Don - I do remember seeing 4 tracks over the years, but I have never owned one. They are still somewhat of a novelty or mystery to me. 8 tracks on the other hand... As far as my location, maybe I should revise my it to read South Central Missouri. I'm in Rolla. Definitely not far away at all, but I don't get to your neck of the woods too often.
Mopar - I have found a few examples of the '51 car plate. I'm not sure if Missouri will let you use a car plate on a truck or not. I was really hoping to have one custom made, since I know what my original license number was from 1951. Without seeing one, I have no idea what color they were, if and where they noted the licensed weight and if they were single year or multiple year plates with tabs. Maybe this is more work than it is really worth. I do enjoy a little bit of the thrill of the hunt, but after a while...