OK, so I finally got one of the old school Domed Hesalite crystal Moonies. Thanks Dale
There are 3 Major Flaws, two of which can be corrected. First is Subdial spacing and only a genuine movement can fix that. I decided I would fix the other two though and as discussed in this thread, the solid caseback covers the obvious movement flaw so I sourced a gen, and yes it fits
The other fixable flaw is the bracelet clasp. The gen lists Omega Speedmaster Professional and the rep lists Omega Speedmaster.
Fixed that with a genuine clasp