well, you've got a world of options at your disposal. Which one to go to depends on what you're going to do with it, how accurate you want it to be, and what the prop pistol you're making it from is made of.
This simplest way, is to just paint it on. and if you're just looking to have it recognizable as his pistol (say, as part of a one off Halloween costume) you don't even have to paint the same pattern, just a series of gold stripes on black.
if you can find an honest to god straight from the side picture, you could also print it out at the proper scale, onto decal transfer paper, and apply it to the exterior of the prop. (since the pattern is all gold and black, it should print well on a home printer even).
If you want the details to be a physical part of the gun (like in the picture, from what I can tell), you can use a "wood burner" type device to burn the pattern in, or a very small dremmel bit, if it's going on a plastic prop. if your prop is metal, you'll need to have it laser engraved or go at it with a very small dremmel, or even CNCed.
laser engraving, or CNC will require doing the art design prior.
