The older Jem7 DBK guitars had a matte black base with glossy raised areas, but the newer ones are glossy all over. So, depending on the look you want, there are a couple of ways to do this.
For the matte black base plus glossy texture you'd spray matte black over the whole thing, then seal it with a matte clear (you could go to satin, if you wanted). To get the raised areas a bit spikier, you'd wanna touch them lightly with something like a piece of wood. I wouldn't use sponge or a cloth in case they left lint or particles in the paint. Then get a black-tinted epoxy and dribble it over the surface.
If you are going for the gloss finish, dribble your epoxy first (it wouldn't have to be tinted), touch it up with the piece of wood while it's still wet, and then spray the whole thing with black. You'd have to spray a gloss clear over it after this, too.
You could go for that hammered enamel paint that Dakine mentioned, though it's not as suitable for guitar refinishing as either poly or nitro. Plus it wouldn't give you quite the same effect.