Yes, there is a small seal that goes inbetween the mainshaft and the final drive gear. If I were doing this job, I'd also replace the seal on the backside of the inner primary as well.

To replace the small final drive gear seal, you will need a special tool to remove the inner race of the primary bearing from the main shaft. Of course, I've seen lots of times when this seal was not replaced while in there with no consequences.

Also, check the splines on the inside of the front belt pulley. These are bad about wearing. I have seen therm wear to the point that they strip out and no longer drive the motorcycles. If allowed to wear too much, they'll start a wear on the final drive gear as well. You do not want that to happen as it will require the replacement of the final drive gear to repair this damage. High Dollars. Good Luck