Maybe, maybe not.
The problem with collectibles is that their market is highly inefficient and, as a consequence, the collectibles themselves are often illiquid.
We hear a lot about items such as Teddy's Smith and Wesson, but the rest of us don't buy items that are so well known. Lesser collectibles aren't nearly so easily sold.
I believe lesser collectibles are easily sold. The problems is, you cannot rely on prices always going up or even staying level.
Lots of personal value of firearms disappeared overnight when some governments banned them. A classic case is India, where double rifles worth thousands of dollars became almost worthless with a ban on hunting and extreme difficulty in selling and transferring rifles legally.
India even made the export to the rifles illegal, because they were "cultural artifacts".