[TKCR]

Now, for the 81-87 frames:
Pic 1, again the picture is sideways, but the 81-87 frame is lighter and has a grid with springs, that hold it to the frame.
Pic 2, almost all the 81-87 seats tilt. The exceptions are, the Suburban & Crew Cab front seats. They are fixed.
Pic 3, the hinge cover that cover the tilting mechanism. And the adjuster is in the front.
Pic 4, what the frame & grid looks like from underneath, on the 81-87.