Here's a pic of the seat in re-assembled form.

The foam cushion was sectioned and glued back together.
The upholstery is bonded to the foam so it stays together.
Not quite the finished product, but a good base for a future upholstery job or the old favorite, a Mexican blanket over the seat.

This seat may or may not work in your roadster pickup (RPU) due to the seat back thickness.

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One point I want to make concerning RPU seat back cushions, don't set it too vertical.
A rod shop building friend of mine swapped a car for a 29 A RPU that was nicely finished.
The previous owner stuck in a vertical, flat, thin cushion on a piece of plywood for a back cushion.
(The seat bottom was done the same way, totally flat etc.)
The object was to gain leg room, but the car was a bitch to spend much time in.
Wasn't long until the seats were rebuilt into a more comfortable shape.