rob,
I don't know if a pre fit pad will work as these are custom stocks, When I order the stocks I order them with the Limbsaver pads fit to my stock, Gunstocks Inc. will supply the pad, install it and fit it to the stock for less than alot of places charge for just a pad.
Different LOP's will change the size of the butt on the stock so I would guess the pre fit pads would not fit perfect, that is why I order the limbsaver installed and fit to the stock at my desired LOP.