You should be concerned and attempt to discern just where the water is seeping from.
Many TT (Taiwanese trawlers) have a keel that is filled with some sort of media, (many times some sort of concrete, sand and mortar, etc) that are then topcoated with polyester resin to form what we think of as our bilge.
My GUESS is that you are seeing symptoms of a bilge that has its sealing layer of polyester resin (and maybe some fiberglass) penetrated by screws allowing over time bilge water to begin to saturate your keel media.
For boats that are never hauled and subjected to freezing weather this may not be particularly hazardous, but it may be a detriment for a later sale or a serious risk were the boat ever to be hauled and out on the hard during a freeze. My layman fear is it would be a risk of degradation of your keel material, maybe causing it to swell/expand and therefor compromising the fiberglass structure of the keel.
I don't have an answer for how to best fix this - it would depend on how much penetration of the keel material is saturated with moisture and what it would take to dry it out then re-seal it.
The question about fiberglassing over it is entrapping moisture inside a polyester resin structure that happens to be your keel/hull and does that have an negative impact over time? Again I don't have an answer for this as the risk of trapping water against polyester resin would worry me.
I think if I were to do anything I would laminate a fiberglass vent pipe to that area of the bilge, then seal the remaining holes. Have the vent extend higher than you can foresee bilge water building up. This would allow that keel area to vent/dry out over a long period of time without additional water intrusion. Perhaps over time you would find it would dry out, allowing for it to be sealed up.
It would look dorky, but would be a lot less intrusive that attempting to dig out all of the possible waterlogged keel then rebuilding it....That would likely be recommended as the best practice fix.
FYI I was able to find filament wound fiberglass pipe for industry at a relatively low cost that I was able to use to chop up and make into threaded fittings for some refit work to my built-in fiberglass holding tank, so pre-made fiberglass pipe is out there....
For future bilge pump installs, I recommend manufacturing some sort of plastic/fiberglass mount that you can epoxy to the bilge (that you would obviously well clean first) to avoid screwing.
