by VintAxe » Tue Nov 20, 2012 2:40 pm
Yeah, that is the P-46 pickup first introduced by Hagstrom in 1958. From what I've read, the pickups were purchased separately from the guitars for about $150 and then installed in the Hagstrom glitter guitar bodies or any other guitar deep enough to hold the unit. You see the same pups used in the Goya branded glitter guitars from this period.
I don't know much about Bjarton guitars either so I don't recognize the model. Based on the pup, 1959 would be a reasonable guesstimate of age assumming the pup is a factory install. The fit of the pickguard indicates a factory install.
You're probably already aware of this page park, but other might be interested in the history of these pickups.