That is not a concept comparable to legitimacy. It symbolizes something else

In general we consider both Qing and Ming empires of China from this period and have used symbols from both. These do not change when the empire of China changes, much as the interface over in Europe, or for that matter other parts of the world, stays the same regardless of how the game evolves.
The symbol you see beside the number 29 has nothing to do with legitimacy though (and it's not a crown like the one in your first post but I imagine that can be hard to tell in this screenshot, wait for one with higher image quality).