The one that started this hunt, the first known Model 10 Royal:
From the Virtual Typewriter Collection of Evan Pitman:
1913 Royal 10 Serial #X-173084
From the Virtual Typewriter Collection of Drew Saffell:
1915 Royal 10 Serial #X14-226176
From the Virtual Typewriter Collection of Richard Mohlman:
1923 Royal 10 Serial #QX 696203
From the Virtual Typewriter Collection of Ryan August:
1923 Royal 10 Serial #X-754246
Now, if we compare this one to an example after 1197537, can we see a difference in the glass panel?
From the Virtual Typewriter Collection of Adam S:
1928 Royal 10 Serial #X-1204198
Other than the glass bevel perhaps being a little thicker than the earlier version, I don’t immediately see a difference. Perhaps between 745309 and 1197537 the single-glass panel was a little thinner than the later version, and is not listed because the later version is a drop-in replacement? Anyone want to measure the difference?
Anyway, after that little bit of research, I’ve updated the Royal Serial Number Page:
Happy I.T.A.M.! :D