To me, to use the Concours standard from MBCA as a way to define originality does not make much sense.
I view the state the car left the factory as a good start to define original.
Hans, you have to start somewhere, and "as delivered" is about as good as you are going to get for somewhere; to say it doesn't make sense, well, doesn't make sense.
The difference between "as delivered" and "as it left the factory" are simply dealer installed options.
As delivered can have several interpretations, and I suppose it is up to the judges to choose.
If you had a car in an MBCA Concours, and a judge was going to deduct a point for not having a Becker radio, showing them an original dealer receipt for a Blaupunkt installed at time of vehicle purchase would probably save that point. Having an early 80s Panasonic cassette radio would certainly cause a point loss.
I don't know about dealer added side molding--that's a bit invasive and I don't think any Concours standard would allow such a thing…
Yes, a reverberator was a bit before my time. Sounds like something you could have bought at J.C. Whitney at the time!
To Rolf-Dieter's point, the other day while at Sam's Club, I noticed two different BlueTooth speaker systems available. I'd have to think that this is the way to go for ease and quality of sound.