One of the best genuine examples

of a Omega Pre-Moon watch 321 you will find

complete with original stretch band & spare aged bezel.

watch is running but not serviced, can be serviced for a additional charge.

Case No  105012-66

Movement serial No 24537972  year 1966

Band No  1039

Below I have added some extra information answering the constant question of  applied logo or not for 66, this watch is correct for all examples below the original owner had this watch from new, one band end piece was lost is the only issue I can see.

 $3750 (+ $25 S&H USA only Tax for TX of course)

The most famous change on the dial is maybe the Omega logo. From 1957 till 1968 Omega used the metal applied Omega logo on the dial. Most people still like the metal applied logo more then the white marked. The metal applied logo was probably changed into white because of the cost. Omega was the only brand back then using metal for their logo on the dial.

The case of the Omega changed in size three times (see also : History of the Speed master). The first Speed master, the CK2915 was used till 1959. After that, the CK2998 was produced, and was slightly bigger. Since the Professional-mark is on the dial, they use a bigger case (42mm instead of 40mm).Look below for the images.

The push buttons changed from (diameter) 4mm to 5mm in 1962. The CK2915 and CK2998 used the 4mm push buttons and since the production of the ST105003 Omega used the 5mm push button. The left picture below is the 4mm push button and the picture on the right is using a 5mm push button.

The winding crown (with Omega symbol) has changed in size also. The pictures below are showing it

.   

Through the years, a lot of things were changed on this watch. For instance, the word "Professional" in 1966 when it was approved for NASA use (more on that later), in 1968 they (Omega) changed the m the chronograph. Changes on the outside  :  white marked Omega-symbol instead of metal applied Omega-symbol and a flat dial.