Cars are not cameras collectible-wise. But even in automobile collection the more original the better. (Having said that -- the world most expensive Ferrari was repainted from blue to red.)
The issue with Nikon F's is that there were so many changes in the early models and they have been well documented by collectors. What may seem correct may indeed not be. But little worry on your camera since the value is not high, and you just want a ding free body.
Just a word on valuable cameras ($5000 or so) keep the original parts if you intend to someday sell.
Of course the idea is to always keep all original parts and I (and probably most of us) were not thinking to rare cameras, just users that we would like to keep as closed to original as possible and still be properly working.
The dilemma about restoring and not restoring is anyway a hard one, what is a bit funny to me is that a lot of builders do feel that their "creatures" should be fixed to be operative for ever and a lot of collectors feel that just touching anything is "spoiling the original item". The well known watch maker Roger W. Smith even said several times in interviews that he does not use any exotic material such as carbon fiber or rare metals alloys for his watches to make it possible restoration from any good watchmaker in the future, yet I guess that any owner of a Roger Smith's watch would rather keep a non working watch than asking another watchmaker to produce a spare part for the watch should something break.
Since several answers from knowledgeable collectors appeared I'd like to ask a last question: where is the line? Is a CLA "alteration of original"? If during a CLA appears a broken small part can this be replaced? If a part is no longer available should the camera be left non working or is it allowed to produce a spare at the lathe? I would say that for me small parts such springs or gaskets should be no problems where larger items, such as a whole prism should be original but I wouldn't know where to exactly put a line.