You don't have to completely remove it, just take it off the cams. But, I would remove it and reset it so that you are 100% sure you get it back on correctly. One way to do it is to set the motor at TDC with the cams pointing up and then using a silver sharpee to mark the timing belt at each cam gear and again at the crank gear (which requires the removal of the crank pully). This will ensure that you get it back on exactly as it was. That's what I do to make this procedure go faster.