Random gauge cluster question

[Rolling_Thunder]

Alright guys - random question....      my 1973 Challenger Rallye came with a build sheet and fender tag - no where on there does it list a rear window defogger - yet my gauge cluster has a "rear defogger" switch on the control panel....         Is it likely the entire gauge cluster has been replaced at some point ?  There was wiring hooked up to that switch and a random connector in the trunk (where the defogger would be mounted) however there is no defogger in the vehicle...    Now that could have been removed at some point - but the option portion of my build sheet is destroyed so I can never know for sure.    So what is most likely?

- Dealer installed option?
- Gauge cluster swapped with the wiring at some point?
- Car was originally built with it and it didn't get stamped on the fender tag ?

[70chall440]

all the above...  In all seriousness, I do not think the rear wind defogger gets put onto the fender tag although it would/should be on the build sheet. All that said, there are so many options and variables here it will be hard to say. It the wires for the defogger is present I suspect it came with it, however it could have been installed somewhere along the line. As to why the defogger isn't there could be due to it failing and being removed for repair or just removed, or more likely someone was or did install some bigger better speakers.

[AARTA340]

On my dealer promo car it is listed, H31 on the tag. Not sure about a 73 though.