From that era, most/nearly all game used Tiger jerseys and pants had the Tiger’s equipment manager’s initials hand written in pen or sharpie. The Tigers organization was VERY protective of its uniforms and claims that something was game used, when it was not. I’ve even heard stories of Tiger employees at memorabilia shows calling out dealers with “game used” jerseys as fakes if they lacked such markings. Hopefully, you have the real deal (maybe the equipment manager did not mark BP jerseys).