Jim;
My '89' manual shows that bearing as being open also and the rest of them do seem to have seals.
Yes, the lube has no trouble getting into the bearing, but the chunks will hopefully not get in there.

This is a common set-up in the industry, in Suv/trucks anyway. I've never seen it on a Porsche/VW/Audi/Ferrari/BMW/Lambo/Maser trans though. maybe less chunks, or better drivers less miss shifts, or ...........??
Kary

1987 Mitsubishi Pajero "Modified"
The other original Mitsu brother
Northwest Trailmaster