Heres the first part of the explanatory story:
So I've been looking for a Duo-Sonic for a while, there a few around, but they were always in the US or priced higher than I was prepared to pay.
Suddenly a '66 Musicmaster appeared on eBay in the UK, and for some reason no one was really bidding. Knowing I could convert her to a Duo-Sonic without much effort I picked her up for a reasonable price. A non-original hard case sweetened the deal even further.
When she arrived I was a bit worried because the frets were very low, but after a week of playing, I found there was no real issues - in fact she seemed like a "good 'un".
I asked the eBay seller about her history. He was an older chap in Sunderland, who brought her off a destitute gigging musician from Newcastle. He in turn had brought her from a store in New Orleans about 8 years ago.
Theres almost no fingerboard wear at the "dusty end" of the board, its all cowboy chords. I imagine she was used as rhythm guitar for jazz and/or blues.
Anyway, I pulled her to bits after a week - the neck is dated late '65, the pot codes are '66, and the serial number could be '66 or '67. I think the seller is right and she left the factory in '66.
I found some non-original parts - the tuners, which are very old schallers. I don't mind them, they have a nice patina and fit to the guitar. I would like original tuners at some stage, but I'm happy enough. Also the pickup was of all things a 1990s mexican strat pickup with the pole pieces pushed flat(!!).
I'll write again a bit later about the conversion work I did.