If it is, then you have quite a job, BUT, it can be fixed.
One inch on a long pew will barely show, so my first suggestion would be to shim up the end of the pew so that it sits flat even with the warp. This can be done by attaching a triangular shim to the high side of the leg to fill in the gap, so the support rests on its entire length. Or, with a plane you can reduce the high spot also.
Second, you can do this. It will take time for the wood to conform though.
Build a system where you can load heavy weights on the warped area to force it back into shape. Fix the level end of the pew leg to the floor and with the opposite endcontorted, add some weights to force it down. Over time the wood will conform and come down.