I believe that is correct. I have an '84 Texan with the CBS. I think that is the first year of the 336TS (T=Texan, S=Safety).I think that starting in 1984 the extra safety came on all the lever actions.
Woah. I skimmed a little too quick and didn't realize someone already brought it upjust put a rubber o-ring on it. if you ever need it, the ring comes off and its just like new.