Red sub 1973 crown

[MellyVinelli]

Hello,

I have a 1973 red sub SN 330xxxx and I am not sure whether it should come with a triplock crown or whether it was a service replacement. It only saw real AD service in 2012 and the watchmaker there was very knowledgeable about vintage watches. The crown did fall out with the stem and I’m not sure if the crown had to be replaced or not. I don’t remember exactly what he did. But he did educate me on the red sub which was a gift to my dad from my grandad back around 1973 when he went started Pharmacy program in university.

I am confused about whether the submariner changed to triplock crowns by 1973 and when they started the roll out but mainly I just want to know whether this is a service replacement or original.