In 2006 the Mk 12 R/S test set that I used in 1972 was still in use at VAFB.
Not surprised. Some systems hang on forever, or so it seems. When I was a missile officer, the MM launch control center memory units were plaited wire memory technology going back beyond the 60s. I don’t think that they were replaced until maybe the late 80s to early 90s when they had the major launch control center upgrades. Old tech does sometimes work and is proven reliable, so why change it.