I'm one of "them" guys.
But I think you are not going to like my answer.
For starters. I would never try to buy such a gun. For any price. My first doubts start with "appears unfired". If it is really true. I would much prefer that it had belonged to someone who did fire it but actually knew what he was doing. Because, it it really is unfired, it once belonged to a complete jerk who managed a big score line on the cylinder without even firing it. Meaning, he knew nothing about SAA revolvers.
And... If it ever fell on my lap for absolute free... No, I wouldn't fire the heck out of it. But I would fire it(not much mind you). Using the closest thing I could manage to the period Cavalry load to evaluate it as a fighting weapon for the period in question.