Is there a symbol next to the 3 that looks kind of like a shield? That would mean it's a Vet item. You only start earning vet levels when you hit 50 normal levels.
Are you sure they aren't VR3? Does it have a shield emblem next to the rank#? (also, if they have a wicked high damage number they're most likely vet weapons)
is it perhaps the case that the weapon you bought was VR3, so veterenlevel and you are regular level 7?