BUCKET SEATS in a 1984 ??

[TKCR]

The seats you have pictured are actually buckets for the truck. And they take the same track sliders from the 73-76 bench seats. But those are only used on the drivers seat. The passenger seat uses brackets.
Your probably not finding much on the 81-87 installations, because those were actually the high back buckets.
And as far as tracks fitting the cab floor, all the tracks will, from 73-87. It’s whether they bolt up to the bottom of the seat. Certain tracks only bolts directly to it’s corresponding seat frame.