I would replace the roll over valves as well as the grommets that they are in, as long as the tank is out and you are already doing the sending unit.
Roll over valves are the white round plastic parts that are in a rubber grommet on either side of the top of the tank. They act as vents for gas fumes when you are on your wheels, but in the event of a roll over they have a flapper inside that shuts off to prevent gas from spilling out and adding to the already bad day that you are having due to being on your lid.
And like said above, all of the rubber hoses should be replaced as well. When installing the new sending unit, i always coat the top of the electrical connection on the unit with some clear silicone caulking.