SamJH
186
Centenary production statistics
The Centenary was a limited production watch in 1948, in 4,000 pieces, with the 30.10 RA PC AM JUB calibre. The movement serial number should be 1075xxxx. This watch had an exterior engraved caseback of laurel boughs and the word "Centenary". The interior of the caseback includes a reference number 2500 and an eight digit case serial number that should be 107xxxxx.
A smaller version, also called Centenary, was produced the following year in 1949, in 2,000 pieces, with the 28.10 RA PC AM JUB. This watch did not have the exterior engraved caseback. The interior caseback includes a reference number 2499 and an eight digit case serial number.
The Centenary was Omega's first automatic chronometer, but not their first automatic. Omega had produced and sold automatics since the early 1940s (1942 I believe).
The case, dial, indices and hands are all 18k gold on both Centenary models.
Not all that glitters is gold, or is a Centenary, however. Omega continued to produce essentially identical watches with a different reference number, in both sizes, for several more years. But these watches did not have the Centenary engraving, did not have the same movements and were not marketed at Centenarys. These later watches did not have 18k gold faces. Some were cased in 14k gold.
Omega changed their calibre designations in 1949. The designation was formerly engraved under the balance wheel on the base plate. Both Centenary movements included "JUB" for Jubilee (100th anniversary) in the calibre designation and this was engraved under the balance wheel. Both movements were only used in the Centenary.
The new three digit numeric designation was engraved on one of the bridges. The larger Centenary movement was renamed the calibre 331. The smaller chronometer movement was renamed the 341. I have never seen a Centenary of either size with a calibre marked with the numeric calibre number. It is possible they exist. The 331 and 341 were only used in the Centenary per the Omega Saga.
I own two Centenarys and a later variation of the smaller chronometer movement, the 343, which has the fine index regulation used on the famous 30 T2 movements.