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Interesting that they didn’t seem to have changed the crown at service - which was a common part of the service at the time as it is part of the waterproofing system.
This style of crown was only used for a short period of time around the early 60s and less frequently used on the doglegs than on the 14381/14393.
It’s possible that crown type was available in 67/74 but the decagonal crown was ubiquitous for the dogleg by then.
Whatever the reason, it’s a nice period quirk of your watch and infinitely easier to use than the decagonal crown.
👍