Just in case anyone else runs across this, the dealer got in-touch with Merc directly on this question. Turns out this is the new design for the "Dust" seal on these caps. They rolled this part out with no communication to the dealer network.
Always been a weak point of the whole ram design. Just about tto replace my port ram end cap too. I found one of the older design on fleebay for about 1/3 the price locally. Wish I'd seen this before buying....
