Stippling is very commonly used on modern guns. On metal, plastic, and wood. It's been very popular on wood stocks of European guns, and in metal engraving, since at least the 1600's. The Book "Steinschloss-Jagerbychsen" (the Jaeger book that Jim Chambers sold) shows several examples. I believe the book "Steel Canvas" showed examples of American work in engraving dating to at least the later half of the 19th century. Primarily factory engraving on stuff like Colt revolvers. But, honestly, it's been a few years since I've looked t that book.
Clearly, the rifle example you showed is of European styling. Stippling would be appropriate on a German Jaeger.
Stippling tools are sold by Brownells. There are lots of how-to explanations and videos on the web. I've never done it myself, but from what I've read, most people use simple tools (like nails) rather than buying special tools. The explanations make it sound fairly simple, but a lot of practice is needed to acquire the "bounce" skills to get good looking work.