From the look, the red one's lunette has a NET layer and the blue(I think it's a later issue) 's lunette is plain.


Also I can smell strong vinegar from the 10,000 but not 50,000
You can see the two bubbles from the red plaque.
Maybe it's just the condition of the blue 50,000 is still good that's why no smell. But the text on red I can feel its bulge from the surface and the text on blue plaque is flat.