On mine it's balky, you can pull it out, it goes back in but with difficulty. I think what it needs is to get it out of there and lube or free up the retract mechanism, it's basically a window blind type of thing. To get it out I believe at least one side of the inside corner panels needs to come out or get loosened enough to get the ends out. And the rear panel that goes over it can't bind on it either. I haven't wanted it enough to start taking off panels, I can do that, but it's not my favorite thing.
To me it's limited usefulness because depending on where you like your seat position it can be too far back for the thing to engage the slots. Also with the tinted rear windows it's pretty hard to see in there anyway. But if you want it, search junkyards I guess and make sure it retracts nice before installation.
I suspect what happened is that it was binding/springs weak and wouldn't retract then it is setting there worse than not being there so someone just took it out.
You didn't say if your truck is 4x4, I was curious because looking at the sales brochure it looks like you could have got manual xfr case and manual hubs with an auto trans which I think you could not get in '97, if you got auto trans you were limited to auto hubs/elec xfr case. I swapped out my hubs for manuals.