I believe 1953 was the first year Chevrolet offered the optional side mounted spare in the rear fender. Prior to that (Art Deco and back) they were mounted on the side of the bed (not in the fender) or front fender mounted (1934 and back).
So, who has a factory right side mounted spare on a Chevrolet truck from 1953 and up?
Mike B

As Mike knows: 1953-1955st (47nd-1955st) factory right-side-mounted spare tire on a GM truck would be scarcer than hens' teeth?

However, does anyone want to speculate why GM put the outside spare on the driver's side?
(maybe that is related to the reason why the outside door lock was on the passenger side?)