Pulling the head is probably the wise thing to do considering all the junk you found in the rest of the system. Reason says the block will be the same. Not sure how much money or a PIA it is to get the rad tanked, but now would be a good time for that too.
But most of us would likely just change the pump based on wishful thinking. Then be really irritated we didn't clean the block too when we knew we should have.
