Well, it arrived today, and after three hours of acclimation time I took it out of the case.
Immediate impressions:
The case sucks. It gives me flashbacks to the days of chipboard cases and I don't like it. It's in good condition, though.
The tuners **suck**.
I dare say it's legit. It's SO clean except for the odd lacker marks. Given the spiderwebs and massive dust-bunnnies living inside the body, it's easily 50+ years old and it's in great shape. Using the borescope it certainly looks like the pickups and electronics are all original. It plays great and the Guildsby is smooth as silk. Only issue I see is that the bridge is sitting funny, but I'll know more about that when I take it all apart.
Pics later today.