I worked as a fingerprint technician for my local police force some decades back. It surprised me when the officers would tell me about how criminals would try to pretty up their guns.
It wasn’t as if street level thugs would send their guns off for gold engraving. Instead they would paint them with nail polish, or wrap the grip with a brightly colored tape. If they used a shotgun to guard their crack house, then they would favor sidesaddle ammo carriers with different colored shells.
Some of this stuff would not effect the reliability of the firearm, but the painting and nail polish certainly could. Lucky thing that most criminals are dirt stupid.
Decorating guns on the cheap is certainly nothing new. Frontiersmen in North America would buy shiny brass tacks at the fur company trading post, and while away cold evenings in their rude shacks by carefully driving them into the stocks of their muskets to produce eye catching patterns.
That sort of thing pales besides how the rich spend huge sums in order to create works of art out of functional self defense tools.
Our good friend knirirr has been kind enough to clue us in to this web page, which discusses how the famed jewelry and luxury goods firm of Tiffany & Co engraved a number of guns in the period from 1880 to 1910.
The material most commonly used was silver, the worksmanship is without peer, and the engraving is amazingly detailed. Click on the link to view a sample of these works of art.
Of course, I am a most practical man. The thing that springs foremost into my mind when seeing such silver masterpieces is that they would be just the thing if I ever had to pistol whip a werewolf.