Dave - if you post this question around various forums you are certain to get all manner of responses from yes to no, however the reality is that Mopar tried very hard to use up all of the parts it could. My 70 Challenger had some odds and ends that should not have been on the car and were from a 69 B body (mainly some E brake stuff). It is not only possible but likely that they put 70 mirrors on a 71 to get them out the door.
As to a "list of parts", good luck with that; "experts" have been trying to figure this out since Mopars became collector items but I personally do not believe you could ever develop such a list because there were multiple plants with multiple policies and varying degrees of parts available. The one thing you learn quickly with regards to Mopars is never say never. we have seen all sorts of weird things that should not have been but were. There are generalities of what should and should not have been done but there are always exceptions. This is one of the things that drives the "experts" crazy because they in many cases make a living off of telling people what is correct and what is not, however it has been proven many times that they do not know as much as they think they do and the good ones admit that up front. All this said and in your situation, while it is possible to have 70 mirrors on a 71, if you were going to promote the car as "original" you would have to provide proof that it came that way, something such as pictures of it on the lot, 1st owner documentation, etc. Without that, everyone will say it is wrong despite any circumstantial evidence you might have (such as they were on it when you got it and did not look like they had been removed or replaced).
Post some pictures of the car.
