It’s been quite a while since I worked on mine, but I’m thinking the seal is leather,
and yours looks intact, and it might be best to leave it alone.
Those old gearcases used grease that was designed with water ingestion
in mind. Even if you were able to put a modern lip seal in there, the driveshaft
is likely to be pitted or grooved and the new seal would leak anyway.
Perhaps someone in the know will give you better advice.
Prepare to be boarded!
