Should be Crash, River's gun, it usually ceases to be a quest item after receiving River's text after finishing his last quest, but yeah It's a bug tooNot only Johnnys clother there is also a gun or two marked as quest items, at least one can't be put in storage also.
not only they rewrote the whole story plot and made johnny the main char of the game they also seem trying to force you on this gear... hail Johnny <.<I don't understand jhonny gear since they are not even used in any quest.