Hello pitchpole. no the seat and post are not 'one'. while that is not the best type of post available, you can fromove the seat and put a new on it. you need to loosen one of the nuts, that will loosen the 'clamp' enough so you can get the seat off. if you check you local bike shop they might have a bin of "take off" seats and I am sure you will find one you like better than that one for a decent price.

and remember that old torture device was what most of had to ride back when that b ike was new. and for some a seat like that in good shape is more comfortable than the new super thin super light ones we have to use.