It will go up in value as a "unfired", but I don't think it will be worth enough in any of our lifetimes to worry about.
I have dozens of S&W's, so what I would do is probably let it sit in the safe for a while, while I "debated" whether to shoot it or not.......then it would bug me to not know how it shoots or even if it shoots.......and I would eventually put some .38's through it.
I have a 6" 28-2 that looked unfired, or had maybe a few rounds on it. No signs of shooting whatsoever. I didn't feel an increase in a couple hundred bucks over the next 20 years was worth having an unfired gun laying around so I fired a few boxes of .38 through it. IMO shooting .38's through a Model 19 won't hurt it a bit, I just wouldn't run a bunch of .357 through it.