A couple of things to add to "dead nuts on" advice you just got.
This is probably a foreign-made import. Verify country of origin. "Why?" you might ask. Apparently Spain's proof (safety testing only) regulations are significantly less stringent than, for example, Italy's. I refer to safety concerns not functioning.
Take a look at the innards of the lock. Budget-priced quality control will blare out at you -- lack of polishing of parts, coil springs rather than "V" springs, soft sear and tumbler, etc.
If it is a flintlock, look for a lip or ridge on the inside of the cock (you'll call it "hammer"). It is supposed to be there to arrest cock fall after ignition.
If it is percussion cap lock, is it drum-and-nipple or patent breeched? If paten breeched, does the paten breech have a fence (that's what it looks like on the rear of where the nipple is) to protect the shooter?
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Everybody has his quirks and preferences. Your first two priorities are to shoot with people who know what they're doing and are willing to share the knowledge; and to do enough basic reading on the subject that what these people tell you will make sense.
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I suggest you ask the National Muzzle Loading Rifle Association web site if they have a charter club in your area.
