'99 Sierra Seat Problem

[1999gmctruckman]

I searched and didn't see a fix so I'm wondering if anyone has experience in getting a manual seat to slide. It is a 3 door (passenger side) extended cab and the driver's seat won't go forward or back. I think it is on the inside rail (closest to the center console). It looks like there is a "pin" and a plastic piece that is not disengaging when I lift the lever in the front of the seat or the lever on the side that allows the seat to lean forward and then slide forward when someone needs to get into the backseat. The "catches" on the sides of the rails disengage on both sides so I think it has to be this "pin" that is supposed to go up and down.

 

Can I just remove the pin or will it not allow the seat to lock?

 

Thanks for any help anyone can offer!