while I have never changed a stop light bulb on the QP, the manual says it is an easy DIY.
Open the trunk lid, then open the small flap on the covering panel in position with the light ( the brake light the lowest one in the red area)
rotate the bulb holder in a counter- clockwise direction and slide it out.
remove the bulb by slightly pushing in and rotating in a counter clockwise direction.
insert new bulb and push in and rotate clockwise
insert bulb holder and rotate clockwise
close the flap on the access panel.
I don't see a bulb number. It is a combination tail light / stop light, so it is probably a 1034 or 1157 ( at least that is what they were 40 years ago!)
2008 QP GTS Nero/Nero with red stitching
Formula Dynamics DBW, Larini Sport Mufflers and X- Pipe