1:700 scale Perrys are almost all waterline. You shouldn't have to file the shape of the hull into mounting pegs.
What you need to do is epoxy some hardware nuts into the bottom cavity of the hull to receive a bolt up through the base.
What, you cemented the bottom plate onto the hull without planning ahead. You are scr*wed now!
Ship modelers should always plan their mounting method in advance by planning for a pedestal or waterline mount. This includes provisions for mounting hardware early in the construction phase - before adding details which will be crushed by a later addition.
If you have not cemented a the bottom plate on, go to the hardware store and buy some nuts & bolts. Epoxy in place.
If you have cemented the bottom in place and you want the model to be removable from the base, drill an appropriate sized hole in the bottom plate.. Carefully thread a nut into the hole. Be careful to not strip threads which are being cut into the plastic by overtightening the bolt. the model will be removeable, but you want to limit the number of times it is removed from the display base to limit the chances of stripping the threads.