Here's a truck with a "1R" id. I believe that the "1" indicates the plant, so your truck should have been made at plant 6 (Oakland) instead.

https://classiccars.com/listings/vi...e-truck-for-sale-in-auburn-indiana-46706

https://forums.aaca.org/topic/134575-early-chevrolet-serial-numbers/

Last edited by Gord&Fran; 03/16/2022 6:34 PM.
Gord 🇨🇦
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1954 1/2 ton 235 4 speed