Regulator store is next to Featured store and both have the exact same items. Who planned that? That’s kind of messed up. (shrug)
My guess is that originally they were separate stores, one for armor, one for crafting materials.
Then they recorded all this dialogue for the two npcs.
Then they decided to merge the stores into one and kept the two locations since the work on the npcs had already been done.
I think the original idea was that there would be one store for javelin customization items and one store for resources.