To yenningcomity, be careful if you decide to take the gun apart for cleaning. It's essentially a Rube Goldberg Device that fires bullets. There's also a ridiculously tiny screw on the "roof" of the trigger guard that you will need to remove to take the gun apart. You'll probably have to go to a jewelry shop or the like to get a screwdriver capable of removing it, and if you do remove that screw,
DO NOT LOSE IT! It will render the gun non-functioning, and Mateba is no longer in business, so the odds of sourcing spare parts is about nil.
It sounds like, since this gun wasn't in the case, that it didn't come with the secondary recoil spring. In order to shoot .38 Special loads with reliability, you'll need the lighter spring, however, even with that, it probably won't be 100%. In my experience, the Mateba likes .357 loads, though they don't have to be hot.
I believe the original had two barrels (and I think some would switch between .357mag, and .44
You can't switch calibers, but one of the cool things about the design is that barrels can be quickly and easily swapped with a special wrench that comes with the gun. I think some models were sold with multiple barrels, but most were not. If you look at the end of the barrel (make sure the gun is unloaded, safe, and no ammunition is present in the room) you should see two holes. Those holes are meant for the barrel removal wrench. If possible, I would suggest going to a machine shop and seeing if they can fabricate one for you, as there's a chance that the barrel will become loose if you shoot the gun a lot.
BTW, do you watch 'ghost with out a shell'
You're thinking of
Ghost In The Shell, the cyberpunk anime film directed by Mamoru Oshii. It's fairly well worth watching, as it's a pretty solid example of just how excellent Japanese animation can actually be. The sequel,
Ghost In The Shell II is easily one of the most visually astonishing science fiction films I've ever seen. Easily on par with
Blade Runner.
The music in both films, however, is utter crap.
