You bought that car in the mid 70s Terry and I believe it was a one owner car. I highly doubt the original owner would have removed them. There should be signs in the seat covers and frames that would indicate these holders were ever installed.

Those of you that think these cars were made with cookie cutters have no idea about assembly line products and quality control in the assembly plants of car manufactures in the 60s and 70s. These companies were not making art and the cost of shutting down a line because a part was the wrong color, installed cross threaded, did not have the right casting date or number or a sticker was installed a slight angle or a tape line was not straight. Some errors were caught and some were not. The problems with 'Reference Restorations' are they are generally referenced to one example which may or may not have been representative of the model.
Ok, maybe a red button when only black was only available might be inaccurate. How do you know this wasn't a dealer unit, that the dealer principal ordered for his wife,he was shocked to see a black seat button because the one he saw at the dealer introduction had red buttons, had his staff paint them red, the car survived as original other than that change until it was restored in 2012 and the restoration shop kept them red as they were restoring a survivor car????

Get off your high horse and join the real world.
There are anomalies found with any of these cars that defy pigeon-holing by so-called experts. We can all find, and have found evidences of this, hemi brake boosters on 318 cars, cars with natural latches when the manufacturing date could indicate painted, 70 hoods on mid 71 cars, engine casting dates that defy logic. Where you there 44 years ago?

By the appearances of that interior I think most of us could accept that Challenger as it is.