dealer installed???

There are plenty of 'documented' factory 'errors' and the reality is assembling a car is a job and people make mistakes on the job.
Dealers also install items after the fact.

In the end, I'm no expert, and I doubt anyone is on how a car came from the factory.

I met an old time Mopar guy a few years back and asked him his opinion on my green seat belts in my green car with black interior, (dated prior to my build date no less).

Everyone else told me there was no way it came like that, but he reminded me that it could have been a mistake, or the way it actually was built- either by the guy who put the seat belts in that day because that was the way 'he' did it, they ran out of black and would use the exterior color in those situations, or for a brief moment in time they matched the seat belts to the exterior, (on certain colored cars, or not).

Then I find a member on here who has a 68 Barracuda, green exterior, black interior, green seat belts- and he bought it new and has had it ever since.