First off: BEAUTIFUL WATCH!

The cal 321 Speedmaster is one of my favorites, and the '66-'67 is the one I've always wanted, congrats on keeping yours in such nice shape!

As to the bracelet, can you have a look on the inside, around the clasp and see if it mentions anywhere USA or made in USA?

 

Does the bracelet say "Swiss" or "Swiss Made" anywhere on it at all?

Reason I ask is because if it was bought new in the USA in that era, or if the bracelet was replaced in the 70s so in the USA, there were many bracelets that were produced by Omega USA instead of Omega SA in Switzerland. I've got an old Omega Constellation that came on a bracelet that didn't match anything Omega officially made, but it was produced in the USA by Omega USA in a different style.

There's nothing wrong with a USA spec bracelet if that's what it is, and its likely to be very rare, but for comfort and correctness from a Speedmaster Pro point of view, you may want to buy a new Swiss Speedmaster bracelet.

Robert Broer (who's actually a member on here) wrote a very good article on Speedmaster bracelets here: http://www.omega-addict.com/reviews/bracelets/

 

The bracelet could be 1975 but the watch is definitely older than that, see how the Omega logo is an applied piece of metal? That was only on the earlier models, and the fact that it says "professional" on the dial means its likely in the 1966-1968 range, which in my opinion, is the best year range for a speedy. The bracelet is most likely an American made Omega USA bracelet which is why it doesn't fit (and why it probably doesn't have Swiss or Swiss made on it) and that was common at the time, Rolex also had their own USA made bracelets during this period.

Personally, although the bracelet is ok for a USA bought Speedmaster, I would change it for a Ref. 1450 or the Ref 1479 bracelet (originally it probably had the 1039 bracelet which is notorious for falling apart as it was poorly made, you don't want one of those to wear, the 1450 is early, correct, and looks good, but in my opinion, the 1479 looks even better and is the ideal choice for that period).

Did you buy it yourself in '75 or did you inherit it?

 

In 2011, it still is the coolest thing to own the moon watch, he must have bought it second hand for it to be a 66-68. He did well, you're lucky enough to have the legendary Cal 321 movement that was discontinued in 1968 (theres a slight chance you could have the 861 if its a late '68 but more likely its a 321).

Two very important pieces of advice that apply to all vintage watches, and especially high value classics like Rolex Submariners and Omega Speedmasters:

Whatever you do, don't touch the dial! The patina and yellowing is original and belongs on that watch, if you replace the dial or replace the luminous markers, the history is gone, and the value of the watch will absolutely plummet. People always regret it after its been done and it ruins a highly collectible and sought after classic.

Secondly, keep the original bezel, it may look a bit tatty, but its worth more than a new one. Things are only original once, and much like the dial, people value the old bezels as they show the life the watch has had.

This is what you call a pre-moon Speedy, because it was made before 1969 when the first moon walk took place, and they are getting more scarce all the time especially in the condition yours is in, so please take care of it

What you should have done to it though:

• Have the movement fully serviced by a quality watchmaker that specialises in vintage Omega
• Have the Hesalite crystal replaced (they're only meant to last 5 years and are considered a replaceable part)
• Buy some Polywatch to keep the crystal in good shape
• Buy a NOS bracelet that goes with a Speedmaster (keep your dad's bracelet some place safe, its probably not the strongest and won't stand up to daily abuse nearly as well as a brand new genuine Speedmaster bracelet for that model year, also that bracelet isnt fitting flush with the case, while a new bracelet will)
• Have the watch fully cleaned, and very lightly polished to remove surface scratches

It will then still look like a vintage classic thanks to the patina on the dial and bezel, but will also look clean and new with the bracelet and case in nice shape

Lastly, consider getting a displayback for it, Robert has one on his and frankly the movement in these is absolutely stunning: http://www.omega-addict.com/reviews/speedmaster/

 

Spot on, as someone that loves vintage Speedys, I've been looking for exactly the model you have, a 1967 production 145.012 with Cal 321 movement. You've got an absolute gem.