The taper pins do need to be driven out to remove the shafts. (I don't know why you wish to do that, though.)
Put the nuts back on the threads of the pins near the top, to help preserve the threads. Hammering will make the ends swell up and there is risk of damaging a thread with a faulty strike. Also, put that cover on a large flat surface so it is is well supported, if you don't wish to crack the casting.