I installed a pair of Watts seals in my '14's rear end 35 yrs ago and they haven't failed. Do they still sell them.
Watts sold out to R.V. Anderson. R.V has been putting his efforts in the Watts clutches, but I don't know about the seals. Are you talking about the cast aluminum outer cap with a modern seal in it?
I don't think the Watts seals are being made but Mr. Watts may have old stock on hand. The seal and O-rings he used in their manufacture are standard items and are available from multiple sources.