It depends - if there was any voltage on the motors, electrolytic corrosion will have trashed them, otherwise if the battery was isolated there is a pretty good chance they are salvageable if you strip them down, wash thoroughly with clean water, dry in a warm place for a week and clean up commutator and shaft surfaces. Lubricate the bearings and reassemble for a quick test and if they run, strip them down again if there was any rust on the armature and stator cores to clean it up and finish with a coat of rust converter, avoiding the windings before reassembly. Non-sealed ball bearings will almost certainly need replacement - if they feel even slightly gritty, change them.