Don't think many people will have this issue, but decided to make this post for anyone in the future who may be looking for this information.
The nut/threaded cap on the power antenna has an O-ring on the underside of it to seal against the trim piece on the rear quarter; mine was stiff and cracked,
but I was able to pull measurements and sourced a new one from eBay pretty easily.

OD = 20.5mm
ID = 18.5mm
Thickness = 1mm

Hopefully this helps that one person in 10+ years that's looking for something as specific and insignificant as this. (It's ok, I'm that kind of person too )

 

Good to know! Thanks for posting this!

Dale

 

Someone should start a compendium of replacement parts.

Another is OEM Nissan part #46584-S0100 is a perfect replacement for the clutch pedal rubber stopper, which is NLA from Mazda.

 

Yeah I used that stopper for both the stoppers on the clutch pedal and the one on the brake pedal. Works great for all of them.