Boat Grommet Repair

[Mugz]

My buddy has a 13' Whaler that he has had for 30 years.
The boat originally had snaps to attach a cover over the top...they have rusted out and left holes the whole length of the boat (both sides). Last year we drilled out the snaps and put in some grommets (not a snap) to fill the holes using some clear RTV. This worked great, but the grommets we used were not Stainless. So we are back to square one. We thought of using some pan head stainless screws in the same manner. I cannot find any snap in plugs in stainless steel.
Any ideas on how we can fix these holes? Sure, we could just plug the wholes with some fiberglass repair, but cosmetically it wouldn't look all that great. Looking for something a little more esthetic. He doesn't have a cover, so he would rather not replace with snaps, he just wants to fill the voids.
The inside of his boat is that Whaler Aqua Blue.

[Van]

They make those in white plastic. Some have the tabs too.

I used a couple and sealed them in with 4200. Still there after many years.

http://www.mcmaster.com/#snap-in-plugs/=wc51dn

EDIT:

Theyr'e only sold white and black