LARGE VINTAGE Shoulder/Messenger/Travel bag unisex

PLEASE HELP ME ID THIS BAG!! AWESOME PLAID inside...This smells like leather to me, but there’s no tag, emblems... anything to help me ID it. Just the quality and weight of this bag is incredible. This is a sturdy, well made, probably vintage bag. Outside pocket & inside pockets. Interior lining is this cool plaid and its spotless. Looks brand new never used. Adjustable strap, brass hardware. Small "natural blemish” on bottom makes me think this is leather. Unisex! 12” high, 11” wide - 6”