I would definitely recommend applying a non-hardening w/shield sealer around the pinch weld and the glass. My 48 spent its entire life in AZ so rust in not a problem, BUT! I spent a considerable amount of time cleaning up the pinch weld area especially at the A pillars. Eliminate all the spot weld sharp edges and mismatched panels the best you can. Not much automation and zero robotics in 1948 produced a body that fits like socks on a rooster.

1948 1 ton