You just need to remove the portion holding the shift boot to tell. Unscrew your shift knob and the trim piece is easy to remove. Then remove the 4 screws holding the rubber inner dust boot and metal plate assembly. Be careful not to tear the rubber boot. All the aftermarket shifters I've seen have a logo or name on them just behind the shifter arm, and are machined from billet aluminum. I haven't seen my stock shifter in so long I forget what it looked like, but there is no mistaking a stocker for an aftermarket one.