Difficult to say. A side view of the bird standing up would help. A Serama should have a tail that is carried high over the back. An OEGB will have a tail that is carried lower.
Another way to tell the difference is to check the skin under the feet. If it is yellowish there, then you may have a Serama or Japanese bantam. If the skin if white or pinkish in that area, then OEGB or Dutch bantam. Later on, OEGB should have red ear lobes but Dutch bantams should have white ear lobes, and that is a good way to tell those two breeds apart.