The design of the screw cover has changed to an extruded rubber strip that locks into the channel. The older foam rubber insert has a habit of shrinking, as you have discovered.
The only source is TaylorMade Products. Unfortunately, due to Sea Ray's vendor agreement, they cannot sell to owners directly. You will need to go to your local dealer and get them to order the footage you need for your model. Apparently, some Sea Ray dealers don't want to order the screw cover so here is an alternative source:
Parts Department
Treasure Island Marina
3605 Thomas Drive
Panama City Beach FL 32413
850-234-6533 .......follow the prompts to get to the parts manager.
Treasure Island is a servicing dealer for Sea Ray and they can usually get TaylorMade to drop ship parts directly to you.
Another solution is to find a closed cell foam and try to match the size you need. This is less than satisfactory because it doesn't fix the problem with the screw cover shrinking.