As far as commemoratives and their value go, I think it depends on
1- what is it commemorating
2- how many are made in the series
3- the specific model of gun
4- who was eligible to buy them when they were initially released
5- how long ago was the series made
6-condition of the gun
7-familial connection to previous owners, if any
If it's something like what you see in the inside cover of
American Rifleman, like a gold-plated Thompson submachine gun (which is a semi-auto version), I consider them sucker fodder. There's no real special thing they commemorate, they'll keep making them as long as they sell well, and they are way overpriced from the get-go. So, they don't appreciate much in value, partly because it will take years to catch up to their issue price.
If it is a "limited edition", it could be re-released again later with the same features, on the whim of the manufacturer, if it was successful on the first release. That reduces the value of both releases, although the buyer pays a premium to get either one.
I think law enforcement commemoratives can be a good collectible. It's usually a one-time batch of a particular gun with features unavailable on a general sale model (such as the Texas Ranger Star engraved on the frame of a TR commemorative); the issue is to commemorate a specific occurrence, such as a 25th, 50th, or even 100th Anniversary of a founding. There is only a specific number of guns ever to be made for that commemorative, so they will always be a non-repeatable limited edition. In some cases, to buy one at the initial release, the buyer must be a currently active officer of that force, or a retiree. That means the market is closed to most potential buyers until one of those guns comes up on the used market, usually from someone's estate. That could make them fairly old. The condition of the gun will also determine value. Mine was exceptionally dirty when I bought it, as reflected in a couple of the pictures below. After several cleanings, I've gotten it to about 95%.
As a case in point, I recently purchased a police force commemorative. It celebrated the 50th Anniversary of the NC Highway Patrol, which was established in 1929, so the commemoration year was 1979. The gun in the issue is a nickel plated S&W Model 29-2.Some have 6-1/2" barrels, some have 6" barrels. (S&W used up their supply of 6-1/2" barrels on this series before discontinuing 6-1/2" barrels as an option for the M29) There are several things about this issue that are unique; One, it was the first time a Model 29 was used as a commemorative gun (29 for the founding year of 1929). Two, it is the only commemorative gun S&W ever made using the acid etching process for the design, which is the shield of the NC State trooper, which was placed on the right side of the frame in the position usually occupied by the S&W logo. It also has "1929 North Carolina Highway-Patrol 1979" acid etched on the right side of the barrel. That the M29-2 is a pinned and recessed gun makes it more special to some collectors because the elimination of those features denotes a milestone in S&W's production methods. Three, only 1200 of these guns were ever made, and will never be repeated. and lastly, to have purchased on at the original issue, the buyer had to be a current Trooper or a retiree in good standing. And as a P.S., these guns are individually numbered, separate from their S&W serial number, so whoever bought number 0001 has what is probably the most valuable gun in the series to a collector. Mine, BTW, is #0835, and has a 6" barrel, so it is late enough in the series that S&W had already run out of the 6-1/2" barrel, so it probably isn't worth as much to a collector as the longer barrel version might be. All these guns were issued in a presentation case, with the Seal of the State of North Carolina embossed on the lid.
If a commemorative can be verified as being unfired (beyond factory test firing), it would be worth even more. So, in any commemorative, there are many factors to consider to determine its value to a collector. For myself, knowing I have a fine P&R S&W Model 29-2 that is one of only 1200 like it, makes it very special to me, more so because I live in NC and the commemorative is representative of my state's Highway Patrol. Heck, this commemorative is 41 years old, it will only be nine more years before they are 100. Wonder if they'll release another one?