Hi all, I am seeking advice on this one please. I have finally decided on a standard Moonwatch as daily wearer, hesalite and steel back, so now in full search mode.

http://www.ebay.co.uk/itm/261994763274_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:ITPurchases made through these links may earn this site a commission from the eBay Partner Network

It is the one I posted about a couple of weeks ago that had an incorrect Mk2 dial. The seller, presumably the watch repairer mentioned in the ad, has since replaced the dial with one he had spare, i.e. the one shown with tritium and stepped/sunken chrono dials, and relisted the watch.
Serial and case numbers seem to match with the age of the watch, i.e. 1970.
However would this still count as a "frankenwatch"? it seems strange to me that a watch repairer would have in his collection a Moonwatch with an incorrect Mk2 dial (although I may be being suspicious out of ignorance).
My other concern is that someone who repairs watches would be ideally cable of cobbling together a watch from spares and passing it off as original.
Is there any way of checking it is original or is it just a case of caveat emptor and if in doubt walk away?
Given the prices that most pre-owned standard Moonwatches seem to fetch, i.e. close to £2,000 in the UK on eBay and around £2,500 from the likes of watchfinder and other high street shops, a brand new one in the big box from an internet grey dealer (they come with full 2 year factory guarantee) is looking more attractive at just £2,400 or so.
Thanks for any advice.