I wouldn't think the chances would be good that someone put it in by mistake especially since there is one in the kit & commonly kits have extras cuz as you know any given kit covers multiple (carb) apps so likely the last person that rebuilt it would be aware of that & I wouldn't think it'd be possible to put a (extra) gasket in where it dont (obviously) belong. If I had a TQ I'd open it up for you. I'd suggest calling "the carb shop" in Eldon Missouri (Google it) & I think he'd be kind enough to ans a 2 minute question for you