I would be willing to bet that his spur is still there. Their spurs are actually quite small. What most people fail to realize is that when looking at an adult Ball Python's spurs, typically what you are seeing is about 3 to 4 retained sheds on the spurs. Look at your snake's next shed, and see if it has a shed spur on it. I usually don't see the shed from the spur on the rest of the shed. I have occasionally pulled off retained spur sheds and you see the actual spur, which is quite small, and white (not the brownish color that you normally see). Hope that helps, and I would bet that upon closer inspection, you will find a tiny white spur still there.