green bearing seal question

Technically, they say that the o-ring keeps it sealed, but I prefer to put the inner seal in anyway. cheap insurance.

That's what I was thinking too. The inner seal is only $3 at O'Reilly's so it's cheap insurance. My buddy that I asked this question for is disabled and having a hard time getting help so I think he was just hoping this would be one less step he wouldn't have to do.