Here are a few semi-coherent things to consider:
By the time the rabble (that's us, or me at least) start thinking something is a good investment idea, the ship has sailed. I think 5+ years ago would've been the right time to start thinking about grabbing older guns such as Pythons, they've already appreciated a lot and I don't know how much more room up at the top there is.
That said, as far as I know no one has plans to make any more, so it's not like its a "bad" idea.
I wouldn't buy one I couldn't shoot (without drastically lowering its value). I'd much rather have two firearms I could shoot than one I couldn't. And you'd only need half the increase per gun to break even, so to speak.
I also see the gap between fired/unfired narrowing, with more room for appreciation at the lower end. Just look at the prices crappy condition older model S&W's are going for, let alone the good ones.
With those caveats, luck on the purchase!