jolyon
·Be careful. IMO, that's not a reasonable stance for a serious seller who actually has the watch in his possession. So make sure it's not a scam and that he actually has the watch.
What does "in order" mean? You don't know what year it is, so you don't know if the single step case-back is right, you have no idea about the serial number. It sounds like he thinks he has something that is much better than it really is and I expect that his asking price is ridiculous. Bezel, hands, and pushers alone will set you back a lot to make it right.
You can't really judge condition accurately with the plastic. Well anyway, if you see it in person without the plastic and you don't like it, you can always walk away.
By ‘in order’ it should have a stamp on the caseback for 105.012-66 HF and serial number in that range.