There've been a number of threads here about the NAC guns. (Do a search...I'm sure you'll find enough to keep you busy reading for quite some time.) As you pointed out the gun in question has a Bridgeport address and a NAC suffix. This means the receiver was an "original" receiver, but was later registered and assembled by NAC (Numrich Arms Co, of West Hurley, New York.) Keep in mind, too, that what you're buying is a registered MG receiver. As long as the receiver is intact, all else is incidental. These days, anything that's transferrable can be made to run (and run correctly) if it doesn't run at first. Is it worth $10k? Absolutely not. IMHO, no gun is worth that much, but as they say, "if you want to play, you gotta pay." MGs are like real estate...they ain't making more of 'em, so they ain't getting cheaper. Other than that, considering MG prices in today's volatile market, $14k is a "fair" price.
btw, it's West
Hurley, not "Hurley." West Hurley is a city in New York state. (Or is is that just "York" state???)