Rates of fireballs that don't produce meteorites are probably a lot higher still. There is a lot of space junk orbiting the earth, but I doubt they are falling back as fireballs to significanly effect fireball rates as a whole. I don't think any piece of fallen space junk as been mistakenly identified as a genuine meteorite. The metal contents have been pretty much identified to remove any bogus finds. This velocity is still very high for space junk.
Persistent trains are also very prominent and long lasting for meteors that produced meteorites.
I wouldn't rely on persistent trains for space junk determinations. Personally, I'd wouldn't worry about trying to make a distinction between space junk and genuine solar system debris unless a piece was found to be analyzed.