What S&Wchad said....
I've always gone with the "3T's" being a non-S&W description of TT, TH and TS for all models so equipped and not delivered in a presentation case. Cased guns, especially those produced during the Bangor Punta years, were always expected to be full target with all N frames, except the 27's and 25's, having a WO and RR. From my recollection I never saw a "3T" fixed sight gun but I'm sure they must have existed.
All the guns we described as "3T's" had those features and were most commonly seen on 4" and 6"
K frame model 19's as well as many other "K" models including 6" and 8 3/8" 14's, 17's, 18's (4") and 48's.
Configurations were often unpredictable and many times apparently random. We would sometimes see a target hammer on a gun with no target trigger...or visa-versa. Target stocks were often ordered and delivered on models, like the 28's, that were most commonly delivered with magna's.
And so the confusion and debate goes on today. What is and was "correct" can be as difficult to determine as what is not. About the only thing that can be reasonably relied on is the assessment of
original owners who can attest that no modifications were made to their particular unusually equipped firearm.
Never say never to any configuration from S&W. My own observations and conclusions have made a fool of me more times than I can count...
JMHO