SPX Taking on Water

[CDestry]

I have a 1995 SPX that is taking on water slowly. I have checked the bailer hose and all other possible areas with no success. The only other idea I can come up with is that the Rear Driveshaft Seal is leaking. Is this a possibility?
What is the difficulty level of replacing the seals?

 

[JPX]

The carbon ring is the likely culprit (were these on 1995s?) - effectively the rear driveshaft seal.