An item will have the text along the lines of "You have no added this item to your wardrobe" or something like that under it, if you have not unlocked it
I used Ludwig's Blade up until I got one of the DLC weapons. And yea, for Djura....if you let him charge you when you go up his tower, do a quick dodge, then shoot him, he should fall off.
So fucking mad. I'm going to CA for work for 3 weeks and I'm scheduled to leave Monday......Won't be able to play I Am Setsuna or the pre-patch until I get back on the 7th of August.