Did a little surfing, it looks like the aftermarket ones are held on with double sided tape, instead of the retainers.
Looked in the factory parts manual, and they don't list any type retainer for the weatherstrip.
It maybe part of the factory tailgate, and if you got an aftermarket version it may not have it.
You may need to got the double sided tape route
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.