I have posted this several times on several boards and got nothing but static. There is a variant out there of this twin lock sub crown that is different than the ones seen from the early 70s/late 60s(after they moved from the twin lock to the trip lock). The "best" I can come up with is that Rolex Geneva had service crowns/tubes made "recently" although I have no evidence that they did. I have posted several threads on the subject but all I got was static. Strange.
The examples in this thread (http://rolexforums.com/showthread.php?t=134413
) of the variant I have only seen on watches where the crown was replaced at a service. The one in my case was sealed in Rolex packaging (not saying that means much though). If you can, post some pictures of the crown from different angles.
There are aftermarket twin lock tubes..