When I did my 3.4, they didn't list any flywheels for a Fiero. I knew that I could get one from a Beretta and they had them listed. The pre-88's have no substitute. TFS may be offering a compatible flywheel from another GM vehicle.
Harmonic damper pullies aren't available, either. You'd need to go to someone like Damper Doc or have a 3.4 pulley re-cut.