I'd imagine you'd have holes where power window buttons are, just find some door panels with out power windows, I'm assuming since its a Silverado, you probably have power locks? I know they have door panels with manaul windows and power locks, our 82 surb has em.
I dont know what the inside of a door with power windows looks like on these trucks, but you probably need the hand crank, just pick em' up aftermarket, can't be too much. Alot cheaper than adding power windows