A few things:
1. You might want to post on the Banjo Hangout (Collector's Corner section). Those guys know this stuff inside and out. There's a fellow there named Mike Halloran who is an expert on Vega longnecks.
2. Here's a pretty good article:
3. In my view, the major consideration is this: how does it sound?
4. I'm not sure Deering can help you. They didn't acquire the Vega trademark until 1989, long after this banjo was made.