Last guy had it for 8 or more years, and the idiot before him painted it with the same paint/color as his car (present company accepted if you are that idiot). I don't have the metal bottom, only the plexi (AAMP service says it should be on the "bottom" (the plate I don't have)).

I need to get an RMA and they want the serial number, but I don't know where to find it.
????
TIA.