It seems like not quite.

The width is 50 some inches but the wheel wells are there so you may need some 2x4 or something to keep plywood from flexing over them. And the length of the bed isn’t near 8 feet so you’d need the bed open and the boards strapped in.

This jalopnik article had some helpful measurements: https://www.jalopnik.com/1845231/slate-pickup-bed-fit-every-...