Same numbers will be on the block on the right side very near the rear and top on a machined flat pad.

Something like 4D-1234567 and 5043-1234.
Could give better examples if I had a book here nut that's the format at least. Could also be a 4DB-12345...

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-