From the pics on gunsamerica.com and gunbroker.com I'd say it looks a lot like a S&W 39-2. The 39-2 is a single stack 9mm, most that I've seen have fixed sights...maybe thats the difference between the two?
Everybody has opinions but it is mine that S&W autos dont get nearly the respect they deserve. Granted they are no Sig, but the ones I've shot have been plenty reliable and the price for a used one is usually pretty good.
1. Probably reliable, you would want to give it a thorough thrashing before trusting it as with anything.
2. I dont know when they were produced, try google. They do not make this model anymore (it does not show on their website)
3. See above. Sights, maybe barrel length, maybe frame material (alloy or steel?) Not sure.
4. Dont know if the nickel is original but gunsamerica and gunborker both listed nickel plated ones, so it would probably be safe to assume there is a good possibility it is factory.
5. 4506, 4566, S&W 1911PD Commander size, or anything else that starts with the number "45"
6. You just have to know where to look. Consult google, gunshows, heck who knows it may be able to share mags with a 39. Ask in the S&W section here.
7. If you buy it be sure to give it a good thrashing with a few hundred rounds before you carry it.