The article raises a valid question - which would seem to be easy enough to answer based on the shipment’s destination. If the shotguns were intended for known, legitimate firearms wholesalers / distributors, it would be noted somewhere in the shipping paperwork.
Here is an article from Belgium:
The load was declared and no irregularities were detected by the customs. It however lacked necessary authorization issued by public safety, which is required for carrying high calibre weapons in Italy - even in simple cases of transit.
http://brusselstimes.com/brussels/4584/italian-police-seize-weapons-meant-for-belgium