Oil pump kit???

Ok, oil pump leaks just like you would expect from a 50 year old item. I tried to find a rebuild kit, Melling number is K-66CB. Oreilly’s and Jegs show them, but if you order in about 30 minutes you get a message saying it isn’t available. Pretty sure pump is original, thought a rebuild was a good idea for a pump that is working just fine, it just leaks. Anyone have an idea where I can one with seals and gaskets? 70 Duster with 198 slant.
Cheers
Tim