Doug, great review of a great light.
The GITD and black tail switch covers are interchangeable (which isn't mentioned), so you have even more options and permutations! The switches are assembled into identical tailcaps. Plus there's a forward clickie on the way... And perhaps another LED module!
It's a good idea to take the switch of choice apart, and add the right lube to the threaded parts as well as between the switch cover and switch, and switch cover and tailcap, to prevent the elastomer from sticking to the metal and to add water-resistance. There's no o-ring in the switch assemblies.
(You have one typo: "talicap" for "tailcap".)