I have absolutely no idea what to call this part when I contact my local marine store and ask if they have it.

As you can see in the picture one of the covers for the top outboard bolt hole is missing. This allows water to enter the hull when the splash well gets water in it. I was just a very sticky cover that was placed over the hole, I tried to get the other one off and cannot as it is stuck wery well.

Can someone help please? Is this a common part?