I am looking for a 1969 ST Speedmaster with the transitional case back. I am currently looking at two or three, between £2,000 and £2,300, in good condition. However, before I buy, does anyone have a strong opinion on whether the pre-moon Calibre 321 is the better purchase?
Hard to have a "strong" opinion, as both references have been proven after decades of use. My strong preference is for the 321. The 861 (though qualified by NASA) was never on the surface of the moon, unless an astronaut took their own watch and we just don't know about it. The 861 was a quicker beat movement and arguably more accurate, as well as being easier to service according to those that do. But it was also built with economy in mind. I look at the 321 as the original, only movement on the moon (as issued by NASA), and built to the highest standard of the day before economy became a factor. Having said that, the "economic" 861 is also regarded by watchmakers as more rugged, if I recall (Archer Watches) Al's evaluation correctly. Can't go wrong with either in terms of operation, and possibly favor the 861 in that regard. But for historical significance, it's a 321 for me.
I assume you mean the straight writing case back? This is the back fitted to the 145.022-69 in the 1970's and came in two executions. (Well three if you include the service replacement). It is rare, but does not significantly raise the price. Look at the bottom of this page: http://www.speedmaster101.com/145-022-69/ There are many more 861 calibre speedmasters for sale than 321. The price difference between a 145.022-68 and a 145.012-67 starts at about $1500 USD, but usually more. The disadvantage of a 321 is servicing. I think you are lucky enough to be in UK so you have STS who still can do it. There are so many pitfalls, that if you are asking a question like this, I recommend you read as much as you can, because finding out later on the watch you thought was correct has got incorrect, or replacement parts is disappointing.
Maybe you could take a look at that one, it has already done a week on ebay and was relisted. http://www.befr.ebay.be/itm/Omega-S...961623869?pt=Wristwatches&hash=item5b0720f33dPurchases made through these links may earn this site a commission from the eBay Partner Network