yes after ticketing, on AA.com you can go to 'Your Trips/Check In" scroll down past the itin to where your name is and there should be a link there to edit your information and the field for Redress or Known Traveler Number/TSA precheck number should be available to you to enter and save.
i've just done this 3 times today.
Last edited by VSLover; Jan 22, 2019 at 11:17 am
Reason: ...