I’ve not seen left handed either.
GM had this wheel bearing adjustment figured out, you for sure don’t want it torqued tight, and they accounted for all possibilities and you can back it of as specified without backing it off to far.

I’m guessing two holes in spindle as Jerry suggests, second one probably full of grease.

If still looking for more possibilities check washer thickness and try another more or less if you have one, same idea as different castle nut.

•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-