You don't say what model this came off of, but it sure looks like the style Yamaha sold back in the late 70s/early 80s for the Specials. I kinda recognize the chevron style. If I recall the turn signals came off the bike and got installed on the sissy bar. Can't blow up your photo but I think I maybe see the tabs for that?
Maybe take another couple of pics to help ID it for others?