As a lifelong collector and occasional dealer , I can say definately , , , maybe!

If ya know the market , know what yer buying vs what will sell , what is worth what and where , yes , quality firearms are a good investment.

A smart , and yet honest gun shop owner can make a small fortune , or at least a comfortable living dealing in nothing but used guns.

And the 'net and sites like Gunbroker.com have helped more than hurt the smart dealer.

Some key points.

Modern firearms are hi-volume commodities , not collectables.

Every old gun is not a valuable classic collectors item.

The "Blue Book" is a guide , not a gospel!

Guns advertised , manufactured , marketed and sold as 'commeratives' and 'collectors items' are mostly worthless. Because practically every one of the limited run of 500/1000/5000 will be kept in it's original box and tucked away.

The true collectables were once common everyday made to be used working guns. Quality made them desirable and attrition made them scarce.

You will NOT make any money if/when you MUST sell or want money NOW. The market (collectors with cash) must want what you have. Walk into a shop and try to sell that Chief Crazy Horse commerative Winchester 94. Go ahead , I dare ya. You won't get half of what ya paid unless ya find an even bigger rube.

Now a plain-jane Winchester Model 95 takedown with shotgun buttplate and half round-half octagon barrel in .33 Winchester , which NOBODY wanted back in 1914 , or 1954 , or even 1984 , is worth it's weight in GOLD today.

I saw several of those tacky WWI commerative Colt 1911s get built into customs and get the heck shot out of them because they were going for less than a standard Gov't Model.

Nobody wanted many of the S&W models thru the years , and so they got cancelled. There were so many of some models , that dealers almost had to give them away. Same with any gunmaker.
But today , those unpopular models that had low or limited production runs because they DIDN'T sell , are worth money today.