Over the few years I have been in the vintage Honda game i have experienced the whole spectrum
The good dealers have held on to the old micro fiche parts lookups, or have it available on the computer.
The average dealers will use one of the many websites to do the look ups and plug the part numbers into there ordering system
The crappy dealers will tell you to go figure out the part numbers yourself and send or bring them in.
Also some dealers will only check the central warehouses for the parts while others will also check other dealers for parts in there stock.
If your ever in need of a part and there being useless or stupid, suggest they use one of the many online sources to get the part numbers.