Do I need to remove pins before removing the harp?

While the tuning pins are not actually attached to the cast-iron plate ("harp"), they do pass through the plate. With a grand piano, the plate can be pulled straight up after removing the lid, and can slide up and off of the pins still in the pin block. An upright piano, spinet through upright grand sizes, cannot be slid off of the tuning pins as the keybed limits movement in that direction. If the keybed is fully removed then it may work, but at that point it would have just been easier to build a piano mock-up from plywood and lumber.