I used to own '03 Lagoon
410 S2 and had same problem, but only with STB crash compartment. Port compartment was always totally dry, not even slightest signs of condensation. STB, however, I was not able to find a source and fully fix it.
There is no hardware through-bolted in the bow compartments that I have seen.
Two crossbeam bolts on my boat were installed inside of that compartment, very close to the bulkhead, (other two are on the other side of the bulkhead), invisible from the outside therefore they could no be inspected visually, only by touch, so I still suspect that these were the culprit (I did not get to re-bedding them before selling). My boat also had an aluminum
rail (gunwale) over hull-deck join, that was the other suspicious element. Remember that water sometimes travel uphill, so the leak could be several feet away and water would still be wicking all the way to the bow compartment. My boat also had an spinnaker
eye located over the bow compartment, but that was easy to re-bed and fix.
This is what I would do: apply some bubble-forming detergent around various parts
of bow area (or entire area) and then create positive air pressure in the otherwise fully enclosed bow compartment (you can use leaf blower, compressed air, etc.) and observe whether you see bubbles forming somewhere. Bubbles would hopefully reveal the place where water can enter. It should be easier after that. Using this and other techniques, I was able to make my boat totally dry, not even a drop of water in the bilges and other compartments (except that STB bow crash box