[cadillac512]

At first it would seem that way. However, any excess out-of-flat in either direction will require some extra amount of bolt torque to overcome the warp and bring the head back to flat. From that point the clamping force needs to be brought on up to proper spec. If the warp is minor the chances are pretty good it'll work ok.
It'd be interesting to install the head on a block with no gasket and see how tight the bolts need to be to bring the head down to flat...using a .001" feeler gauge to check.