Hi "Bones", welcome aboard!
Like Wood said, get pics, especially of what we call the neck alignment:
http://www.frets.com/FretsPages/Musician/Guitar/Setup/NeckAngle/neckangle.html
Reason I mention it is because we did have a member here a few years back, who'd bought a New Hartford 12 new, (I think 2010 was the first year for 12's from New Hartford); and wound up having a bit of a nightmare getting a warranty neck re-set.
In fairness, Fender was in re-organization of its service system at the time and the first "fix" was to severely shave the bridge at an apparently less-than-experienced shop, it came out looking like a literal hack job.
Even, then, action kept raising and he was only finally given a warranty exchange guitar after much argument with Fender/Guild. It was finally allowed that the original neckset wasn't stable.
It's only conjecture on my part but I wondered if it might have been because New Hartford started using Titebond for setting necks, but prior to that, Guild was "All hideglue all the time".
Anyway, don't let that scare you off, it's the ONLY New Hartford 12-string horror story I can recall.
In general, owner/members here consider New Hartford builds to be some of the finest Guilds ever made, but that anecdote is a precise answer to your question, and why it always pays to do your diligence where possible.