I'm pretty sure several of my revolvers hold a good value. For instance my 454 super red hawk Alaskan model and my G500 are just a couple. But I don't sell guns, I only buy them. 😊
They do hold their value, the depreciation glocks your referring to are police service pistols, they are priced according to the condition they are in like most guns. If you keep your Glock in pristine condition you could sell it to most people for 450-500. There’s still a lot of demand for Glocks but the company does a great job in supplying their guns to the market, keeping prices down.