remove shower curtain track to install extend a shower??

I left the track and hangers be and just installed the new rod. There is no need to seal the holes because water doesn't get up that high. Well, not if you are taking a regular shower. If you and the missus get in there together and really whoop it up, all bets are off. But if it really troubles you, you might put a tiny dab of white caulk under the screw head before you drive it home. But I really don't think you need it.