Nicki the factory wouldn't have put the Z28 emblem on the fender unless it was a real Z28. This would have been something added by a prior owner. It's VERY common to see Camaro's with Z28 emblems on them. Too common in fact. Chevrolet originally built only 602 Z28's in 1967. Nowdays you can't swing a dead cat without hitting one!!
Don't forget, in 1967 the factory didn't put Z/28 emblems on any Camaros, not even on the 602 real Z/28s!