That makes sense. To me those look like the rivets that secure either the clutch or break hub to there disc. Mine on one side were really loose and you could move the disc on the hub. I ended up replacing all the discs
along with everything else in the gear box. Itç—´ good to check everything in there once and awhile because the planetary gears can come loose and destroy all the gears connected.
Unfortunately you cant see much through that cover. The bevel gear carrier is behind that cover. The discs are on the sides of the gear box and there's a metal casting between them and the back cover. You have to pull the top cover to see what's going on. Maybe yours being a few years newer is different but I don't know.