Engine/Transmission (1998.5 - 2002) Mystery water leak

[2Farr]

When I rebuilt my 5.9 five years ago I used a new Cummins water pump and o ring seal from Genos garage. Well after 26K miles I now have a water weep from the top of the water pump where it meets the cylinder block. It weeps just enough to discolor the paint. The weep hole in the water pump is dry. I checked it with a q-tip.
Taking votes here. Should I just replace the o ring seal or the water pump and seal?

 

[Cummins12V98]

Seal

 

[brucejohnson]

Seal

I second the seal vote...

 

[JMcCoy]

Seal