For best results, you should completely disassemble the pistol prior to refinishing. Remember, these moly/teflon finishes give a high degree of protection from corrosion and also help lubricate moving parts so coating everything that is steel or that slides against another part is advisable. Small parts can be refinished on an old cookie sheet. If you preheat the parts to 150F before spraying, the solvent in the finish will flash off almost immediately leaving them dry to the touch. Flip them over and spray again. Large parts can be sprayed while hung from hooks made from coat hangers or can also be sprayed on the cookie sheet like the small parts I mentioned above. If you screw anything up, most of these finishes will wipe off with a strong solvent like M.E.K or acetone but only if you wipe them off before baking them. Once you bake them, it'll take a sandblaster to remove them.
Also, avoid finishes in a spray can since they don't atomize fine enough. They work but they won't look as good as something applied with a properly adjusted air brush. The cheap, $20-40, airbrushes work just fine.