If the light fixtures are not stock I'd replace them. In this part of the country rust can be such a huge problem that a complete new socket can be a good idea.
Rusty old sockets will give you grounding problems that can drive you nuts.
You can buy stock look taillights from some of the venders, or a generic set of trailer or replacement lights at most any auto parts store.
Chevs of the 40s is in Vancouver and real close to I-5 (on the east side) somewhere north, like 140th or 150th or maybe 160th? Not cheap, but they probably have new stock type available to carry out the door. (Yeah I once lived in Vancouver.)
