regiis - Here's some snapshots of info from the 1929-54 Chevrolet Master Parts and Accessories Catalog P&A 30 March 1954 that provide details on the original stud GM# 3683850 and specific dimensions for your truck.

You should be able to use the dimension data to search and find a suitable stud. Good luck with your search.
Attachments

~ Dan
1951 Chevy 3 window 3100
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"My Grandpa Carl's Truck and How it Became Mine"
1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver)
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