Quoted from pinmods:This whole thing of comparing cars to pinball machines is so insanely stupid, I can't even believe that people post it over and over.
A '65 Mustang has 1 thing in common with a new Mustang. The name. When Ford breaks out the original tooling and makes literal reproductions of a '65 Mustangs, then your comparison will be valid. Until then, it is idiotic.
...even then it is still a repro not an original - even then the new one would cost more than an original since in this case '65 Mustangs can be found all over. Now if you talk low production models, yes they will still always retain their high value to collectors. BTW for the record, Ford did repro the Model A in 1980 - didn't affect the prices of original Model As that much.
This argument is stupid, some prefer new, some prefer original - for people that just want to play the game wouldn't really care if it was new or old? Collectors would want the original - this is the same argument as real pinball vs. virtual, some really don't care if it is on a video screen.
Would the value drop some? I would probably say yes as the overall demand would drop off, but I would think that an original would still be worth more than a new. But then, I doubt the majority of the people that want a MM wouldn't pay over $10k for one anyways (in the "old market") if one became available near them either never mind the ones that wouldn't even pay the asking price for a new one.
The bright side with the remakes, there will be a bunch of new parts for the originals now. 
OP - good luck with the sale.