Do the holes appear to be some sort of plastic insert (like footstrap screw inserts on your other boards?
If so they are possibly there to attach a carry net that was at one time a feature of the Serenity.
Are these holes on the top of your Serenity or the bottom?
If they are an insert (or two seperate inserts, they will be watertight and give you no problems.
Until you get a definitive answer, you can put some duct tape or vinyl sail repair tape over them to
keep any water out.
If you could send me a photo of the holes, we can give you a definitive answer.
If not, I know where there is a Serenity and will have a look this coming weekend.
P.S. May I delete the first post in this thread?
It looks like somehow you cut and pasted the entire menu in .