Ok. Uh well I would have to say it was a vague half-a$$ed bit of info they gave you. I can tell you there are semi-autos on the market that will fail to function before you shoot 500 rnds without cleaning. Any time you buy a used gun you definitely want to take it home and go through it thoroughly and clean it before you shoot. Even with a brand new gun its a good idea. There could be an obstruction in the barrel nobody noticed. I would recommend running 200-500 rounds through a gun before you carry it for defense. You want to be damn sure its reliable.
I don't need No stinking signature.