I have 2 of what it appears to be Hayward Return Inlet Faceplates (SPX1411B?) broken in my pool. Here is one of them (ignore the pink - it's antifreeze):
It doesn't seem to cause any problem, but I would like to replace it. From this diagram (different type, but I assume it's similar):
it seems that it's affixed by 4 screws and no bolts and there is no danger of losing a nut or something. That was one of my concerns - I was afraid that once I unscrew them I won't be able to put it back together. Doesn't seem to be the case, but I just want to confirm to be sure.
Another question I have is this - can I replace it under water? I can see that it pinches/pushes the liner against the return assembly and when unscrewed it might/will leak water in. Will this be a problem? Will I be better off waiting for pool closure next fall and do it then?