For example there was a similar series of items known as the bracelets of storing. they had several varieities. the lesser on said in description you could use it to store ANY weapon by holding it and speaking the command word. up to 8 weapons in one. Yet on the greater variety it said it could store up to 8 magical weapons. see how magical weapon is seperate and above any weapon. as the any actually only implies to any mundane weapon.
Magical items are always exceptions not part of the normal.