"Any idea where/what source I can learn about vintage Chevy truck frame numbers?"
at this forum - if you have a number stamped on a 55 1st frame it's not from GM, Chevy didn't stamp any numbers on the frame until after the 55 2nd series, then as said above, part of the "vin" ID# on the door tag is what was stamped on the frame near the steering box .... also the number that was used on the paper title back then was normally the engine number, although that started changing about 55, if you have anything on the title other than the "vehicle serial number" or "engine serial number" as shown in Tims link it was assigned by the DMV
Bill
