I recently inherited 1/2 of my Father's collecton of firearms. My Father only owned guns he wanted to shoot, and, to a very large degree, the guns I got from him look the part.
I suppose his model 241 Remington, the first gun he purchased for himself new, circa 1946, or so, is worth more than he paid for it. Likely his Silver Snipe would be worth more than the $163 he paid, inspite of it's refinished stock.

But, for myself, and his only grandson, that misses the point by a long margin.

Keep only guns you enjoy using. Any "investment" will be found only there, usually. Your heirs can quibble about what it's worth, since, from what I've seen, few people liquidate before their end.
Dad didn't. I won't. I'm not betting on you, either.
Best,
Ted