How to do it
If you made your Res PRIOR to Opting-In OR PRIOR to entering your Know Taveler Number in your profile, OR was not available on that Res Page, it won't be on that Res and therefore no PreCheck.
Solution, call Res # at SW, and the nice ladies will manually add it to all your PRIOR Reservations. Just did it. Future Res will be automatic of course if logged in..