I doubt if very many people either live long enough, or shoot a particular gun enough to wear out a hook a second time. Keeping the wearing surfaces clean and lubricated should be more than sufficient.
You can go to the main double gun forum and start another thread asking for recommendations on the best hinge pin lube. That's always been a crowd pleaser!
Seriously, a wee dab of any old synthetic grease is all you need. Grease stays put better than oil. Clean and replace it under dirty or dusty conditions before it becomes an abrasive paste.
