The recommendations for races, seals, etc is not an option. You're very far from being concerned with "the fish scale". Regarding finding parts, If they can't be found here, try this isuzu forum; http://forum.planetisuzoo.com/

In your photos, see the shaft sticking out? Near the end, on the smooth part, should be a groove which a circ clip sits in. Disregard that one; it's for auto locking hubs. A little bit in towards the hub, another groove is cut into the larger splined section. That groove takes a 26mm clip for those manual hubs you have. If you can't see that groove, try either pushing the shaft out from the back a little more. You can also thread a bolt into the end nearest you and pulling on the shaft.