I can't guess a specific number, looks like a high AU because of the reverse weakness but the fields are clean. Oh why not... AU 58
This one is the most attractive of the group you've posted so far. I really like that reverse. I think this one is a 53, but I'll bet the plastic has a higher number.
My swag is 55. Something about the toning and lighting that would make me wank to see in hand before buying.
And that is really wise when buying Bust Half dollars. I will buy from an image but have to know the dealer really well. They have to work with me if I wish to return the coin.