M_Boats: mystery screws

Yo, The mast on my 2004 M17 has two official-looking machine screw heads across from the dreaded slot a couple of feet up the mast, but they don't fasten anything to the outside. Anyone know if they are holding something important inside, such as a clip to hold the electrical cables? I can't figure how anything could be fastened that far up the tube, but there they are. I have a similar mystery set on the boom a few inches from the gooseneck, and another set on the mast. The temptation is to take them all out and see what falls off, but that could have unintended consequences of the negative sort. Thanks a bunch, Tom Jenkins Scintilla