My local Scout Shop in Wilmington, Delaware is operated by National Supply. The council asks them to staple a copy of the receipt to a signed Advancement Report whenever recognitions required to be reported are purchased.
Since that Scout Shop is only 20 minutes south of another council (in Pennsylvania) and 20 minutes west of a third council (in New Jersey), they probably get lots of business from other councils. Maybe not so much from New Jersey, since there is a toll for the bridge. I don’t know what they do with out-of-council purchasers. I’ll ask the next time I’m there.