The last two times I've flown I got selected for TSA-Precheck. It seems to be a throwback to the old way of going through Security.keep your belt and shoes on, no unpacking your electronics and some other stuff, Both times I set off some explosive detector and got the private room pat down.
The first time was returning from A2 and had my hands swabbed. That set off the detector.
The second time was flying from Dayton, walked through the metal detector and my shoes alerted. I had worn the same shoes at the indoor range the night before. They x-rayed my shoes and swabbed them again, came back clean. Swabbed my hands and they came back clean.
From my 2 experiences, I'll say if you're selected for TSA Pre-Check, don't wear anything you've been shooting in unless you have time to kill.
YMMV.