mr_yossarian
·Well 25m might be right in the upper case, so it could be a case back swap and then it could be an otherwise original 105.012-66 with a contemporary service bezel. Though we would need a few more digits of serial to compare with known speedmaster movements.
I am recalling the old london watchmaker who told me he would care not which speedmaster back went on which, as he serviced them in batches in the 1970's.
Except here I agree with others that this is a mess of parts, thrown together.
Look at the colour difference in the bridges:
Concerning the serials and references. The last resort would be the outlayers theory but this chart for me: http://www.moonwatchonly.com/omega-...view-of-the-speedmaster-moonwatch-production/