In 1949, you had an L shaped arm that attached to the spare and slid into that track. Very difficult to operate. My theory is that once the spare was removed, it was too much work to replace, so owners would throw the spare in the bed and the remaining hardware away. So today we have lots of trucks with the track attached to the truck frame and nothing else. But the last year of this type of spare assembly was 1950 I believe. Pictures of this are in the Master Parts Catalog, or I can send you a scan of that page of that catalog. There was even a keyed lock for the assembly, which came standard on your year truck.
Difficult to find these spare assemblies, and not cheap, since they are fairly rare.
