The Shops on this page all sell the same Category of items.
A note about Stable Master Shops: All Stable Master's rent 2 of 4 available horses. There is no difference between the 4 horses except appearance. All horses are available for 15 minutes or 2 hours. They do not actually use the Shop interface, the rental is scripted, but it appears that at one time the devs intended to use the Shop interface so the Shop-GUID records do exist.