That's them. I came up with nearly the identical hinge. I didn't care if the hinge was visible like most seem to care about, my van has bid exposed hinges already, LOL!
Maybe one of those small, stationary type flip seats like in a UPS truck, etc... would serve the purpose?
1984 Chevy G20 solid panel van
Factory 6.2 DETROIT DIESEL, 4speed manual, dual A/C, cruise, power windows & locks.