Just some more thoughts regarding crowns, tubes & Rolex...
Some vintage crowns are next to impossible to find. I have tried to 'collect' as many as I can over the years - even if I did not own the watch that a given crown was made for.
Anyhow, stupid me in the end. The reason? Well, the matching crown tubes are most often thee most difficult vintage part to get.
Example: I have a NOS Twinlock crown waiting to be mounted on my 5513. Yes, I have been stubborn and have not had the Twinlock crown+tube upgraded by Rolex Service Center. There's no way in hell it seems that I will be able to find a crown tube for the oooold Twinlock system for my 5513. It might might be time to move on and upgrade to the Triplock system. In the end, it will be better for the general preservation of the watch; however, I refuse to change the crystal to a flat T-19 crystal.
Cheers