Shaun,

a) Insist on movement pictures. seller seems a trader yet he claims he doesn't have the tools to open a snapback? ALL his other ads show movement pictures. When the dial is (brutally) refinished I'd want to see the innards!
b) Insist on high-res pictures of the full IDF number. Then look at the scratches and decide which was there first: the marking or the toolmark.
c) Compare that to the numbers of the 70's Autavias on OTD (and probably your own cave)... they appear very similar. I've no idea of the meaning of these numbers: but different watches with (almost) sequential numbers s/b investigated.

d) In the end it's still a below par 2446c... with a suspect handdrilled Mxxx on it. I'm not convinced yet: in comparison your Argentian Autavia was a nobrainer.

Jurgen