Chris,
Oops, retraction time.
My 1934 ohv uses essentially the same oil pump, but it has been a long time since I had a look at it. I have a spare pump, so pulled the cover off it and had a look. At first it seemed to confirm my memory; a plain face to the end of the gear with a close axial fit in the housing to limit oil seepage.

Then I thought I might as well lift the idler gear out, erp...

The seals are felt, though the one looks like it my be a homemade replacement. It looks as if this is primarily intended to be a shaft seal between the delivery and scavenge chambers of the pump. This is the scavenge side. I did not open up the delivery side to see if used seals on both sides of those gears, or just one.
-Doug