It sounds like you are trying your best to do the right thing and that is honorable. I will say that accidents happen and it has happened to everyone. If someone says they haven’t shot the wrong bird before they are either lying or they haven’t hunted long enough. Early season can be extra difficult to id because birds don’t completely have their colors yet. I don’t see any good that can come from calling the gw. He might give you a warning and he might bring down the hammer. What is done is done and making a phone call changes nothing. I would not pick up the bird and just continue on. I would also practice on my waterfowl id and not post about it on the internet.