Thanks for bringing this up. As the owner of an Apollo 35th Anniversary Speedy it bloody well bothers me. Moreover, as the owner of the Japan Racing Dial Speedy and on behalf of those owners of original Mitsukoshi Speedmasters, and indeed the entire watch collecting community, it actually worries me.
Let's start with the latter first. The only difference between those two watches and a bog standard 3570.50 Speedmaster is the dial and the hands. As the price rises for those rare models there is always the temptation to those less scrupulous than we obviously are to create Franken watches and pass them off as the real deal to cash in on the premium price - it may not be the original modder either, but owners two or three down the line. Now I know you are thinking that replicas have been created for centuries, so let the buyer beware - but the difference in this case is that they are using OEM parts so the modded watch is indistinguishable from the original, making them very hard to authenticate unless you know how to do that. While I appreciate that makes the hunt for one so much more exciting, I could do without that excitement when thousands of dollars are changing hands.
While it is more difficult to fake the 35th Anniversary model due to the special case back, markings and documentation, this allows me to mention the lesser but more annoying issue (in my opinion) about these modded watches. I do not buy my watches so that I can attract any special attention, either on the forums or in real life (very difficult anyway given where I live), but it bothers me that those who mod these watches come onto forums showing off there new creations and strutting around like peacocks getting complements and likes, admittedly mostly by the newby fan boys. Most forums don't allow the discussions of replica or fakes, but in this case we not only allow it, but it is encouraged by the praise of other members.
Let's not kid ourselves about this, these modified watches are fakes. If you put the special hands and dial of a Mitsukoshi on an everyday Speedmaster Professional, Reference 3570.50, you have created a fake Mitsukoshi, not a Reference 3570.31. Go and frequent any of the vintage forums and watch the discussions over minute details of authenticity, provenance and value when the watch has had a redial, was over polished or had an incorrect crown fitted. Then project your mind forward another thirty years and consider how that discussion will go over one of these modded watches. I wonder how much value has been lost in the past by collectors buying faked watches when the parts were obviously not made in the same factory as the original watch - I wonder how much more value will lost when the parts were.
True collectors understand that provenance is everything.