For those of you keeping score at home, the great mystery of the illegible lip tattoo was solved this past weekend. It turns out that basically the first number Caitlin tried with the Jockey Club, over a month ago, was in fact the correct one! (That would be G22021.) The Jockey Club originally said the number was not a match because their records indicated that it belonged to a horse that was a different color than Royal. Well, they were wrong!
The Thoroughbred Racing Protective Bureau did a more thorough investigation, given the partial tattoo number and a complete description of the horse, down to his markings. This investigation, naturally, took a bit more time but eventually revealed that, though the color on his papers is listed as "dark bay" instead of just regular "bay," Royal is definitely a horse called Majinski. (Not Magic Thang or whatever the previous owner thought his name might be.)
And it gets better. Royal really does have some fairly regal bloodlines. His grandsire, Nijinsky II, was voted the UK's "Horse of the Millennium" in 2000. Royal did not, it seems, inherit any of his grandsire's racing gifts, since he never even made it to the track (though he is tattooed, he has no race record whatsoever), so this is a good thing for potential buyers who might worry about the stresses that racing puts on young horses' legs.
Anyway, I know you were all just going crazy with anticipation, waiting for the resolution of this strange tale. Now you can sleep easier at night. You're welcome. ;)