Is it absolutely nescessary to set timing if the main crank has not been moved?

I have a 1987 Nissan pickup with a 2.4 liter z24i engine. I am putting on a new cylinder head because the old one was warped. Prior to dissasembly I marked the timing chain and the cam sprocket so that I could preserve my correct timing, and immobalized the chain by jamming a wooden wedge so that the chain was locked against the tensioners. ( I had hoped I was only going to be swapping out a head gasket) So the main crank and the timing chain have been immobile this whole time. Obviously the valve positioning has been altered since I have a new head. BUT it occurs to me that since the camshaft has a knockpin that fits into the only whole on the cam sprocket, will not the valvetrain return to it's original position once I align the marks I made on the cam sprocket and the timing chain? If so this would save me a LOT of labor since I would not need to remove the timing belt cover to re-establish the correct timing. Am I correct?