I'm pretty sure my the top on my 89 has been replaced but I am not 100% sure. Regardless, the mechanism and bows are not broken and the material is in good shape. However, when the top is latched in, it is under a bit of tension from the front to back as I latch it in. It's enough so that after I drive for a few minutes, the rear latch releases. Also, curiously, the two securing handles at the front, do not tighten the top to the windshield. There is a good gap between the latch cam surface where it engages the windshield frame. Maybe 3/8" on the drivers side. The passenger side seems to be OK. I shim them up with different thickness wedges.

I haven't seen any proper setups so I'm not sure what has worn out or come out of adjustment. I just know that it shouldn't have much tension (if any), and it shouldn't pop out when driving.