Your Firebird is a preFMIC model. The transition period is around 2003.
PreFMIC Jets are supposed to have less routing and are usually heavier than more recent models. A Filtertron equipped guitar will have ceramic magnets whereas the more recent models have alnico magnets. You may also have the worst ever (in my opinion) roller bearing bridge on that guitar. Some also complain about the wiring and the pots in the guitar. Also, if you are a stickler for historical accuracy, preFMIC Gretschs tend not to follow the exact design parameters (body shape, headstock design, fret inlays, etc.) of the vintage originals.
I have a 1997 Red Sparkle Jet. It is fairly heavy for a Jet weighing in a 8.5 lbs. but reasonable beside my 10lb+ Les Paul. Some people find the ceramic pickups 'harsh' or 'weak' but I find that they compare pretty favorably with the alnico pickups (I have a few other FMIC Gretschs as well). They are hotter than regular alnico Filtertrons so comparisons are not so easy to do nor so accurate.
If you have the pictured rolller bearing, swap it out before you make any other changes. In my experience, it DID make the pickups sound thin and weak.
My Jet has tiny, cheap looking pots but neither they, nor the switches or wiring have given me any problems.
Usually, in the used market, preFMIC guitars will have a lower value than more recent models. But MY Jet (except for the body weight) is every bit as fantastic as my other Gretsch guitars. It is very well built and a pleasure to play.