I had the hose clamp in place, lasted about a month or two before it started slipping. Tried to tighten, but would still slip. Went to the dealer for a recall (15304) fix and asked them to change oil and take a look at the seat. They acknowledged the seat issue and the svc mgr said they have a fix, but it doesn't always work. At least he was being honest. They performed PI1183A http://oemdtc.com/12126/front-seat-lateral-movement-andor-click-type-noise-while-driving-2014-chevrolet-silverado-gmc-sierra
Seems solid so far, only time will tell if I need to go back to the hose clamps. Svc mgr said he could order new tracks but he is supposed to perform PI1183A first, and to let him know if it starts slipping again. Appears to be a newer than PI1376. Didn't see any shims mentioned and I do see that black-ish plastic retainer that's in the last picture of the instructions linked above.