It looks like Omega experimented with the Speedmaster case-back transition from the pre-moon "Hippocampus" to the final "Medallion" version with three transitional variants:
- the straight writing (Ref 145.022-69)
- the straight writing - Apollo XI 1969 (Ref 145.022-69)
- the "No Nasa" (Ref 145.022-71)
On the last version it is being said that the NASA approval for the text around the Hippocampus was unexpectedly delayed which is why a small batch of "Medallion" case-backs without the later inscription hit the market. (Final and agreed text used being: Flight-Qualified By NASA For All Manned Space Missions - The first Watch Worn On The Moon)
I still need to take a group picture with all three versions next to each other.
Cheers, HSTE


