The onus would be on the vendor to prove without access to the device that it was one of theirs. Once the statement the gp points out is made I can't see how the vendor could compel surrender of the device for inspection or anything other reason.
I cannot see any court in the land going along with such a request as it would be harassment. Not only that but once it is proven that the device is not the device the vendor states it is then the consignee could sue them, and also probably take the case up with the criminal justice system under regulations previously mentioned. Savvi is on very thin ice here.