No, it is not true. during pre-patch, before they revamped everything, encouraging you to wear appropriate class armor/weapons, I had Stratholme Lily in my bags on my rogue. It did not count towards anything lying in my bag, however, if I equipped the item at the time, it would increase my stats. Obviously this wasn't worth it since I'd lose offhand damage by quite a bit.< Edit: On armory it would count towards your average item level, since it's equipable, but it will not count towards any stats in BGs/Arenas, lying in your bags. If you have DejaCharacterStats addon, you will also notice that you have equipped x/y ilvl. Y being your maximum ilvl that your character can equip with the items in your possession.