92 Jetta Gl Dash fasteners?

If you mean the useless piece of black plastic that goes efrom the bottom of the kneebar back to the firewall, I'd suggest pulling it out and leaving it somewhere harmless (like the back of your garage). If you really want to keep it in place, so that the underside of the dash is cosmetically appealing, there should be a plastic fastener at the firewall (I think it's just left of and above the brake pedal, but I'm going on memory) and a few screws holding it to the kneebar. If you're missing the fasteners (especially the one on the firewall), the salvage yard is probably your best bet to find replacements.