777 seems a lot to be limited. Was there a non-limited edition?
Yes, and yes, as far as I know.
I agree that "limited" is doing a bit of heavy lifting here, but on the other hand it's not uncommon with supposedly "limited" comics, toys and collectibles, for there to be editions of thousands, or even worse, unspecified amounts, so it's sort of lost its marque of exclusivity these days.
That aside, the 777 figure seems to have a bit of an association with Tintin items, thanks to the "for readers of 7-77" tag that was used to advertise the Tintin
magazine back in the day.
The large retrospective history book about the magazine also had a "777" limited edition, in a red cloth cover, and that seemed to sell well, so I suppose that this continues that in a sort of fashion.
There was a "deluxe" edition of the colour Land of the Soviets
when that came out, which ran to 50,000 copies, and included a "making of" section, a different cover showing an alternate image, similar to the black & white edition, that Hergé made, and a distinctive ridged silver spine; the book wasn't numbered, but it came with a separate art print of the "missing page" (recoloured) and that
was numbered. There was an additional
art print, showing Tintin in the speeding car just after he gained his quiff, plus a paper carrier bag, which was distributed to early buyers, or people who attended a book fair or book launch, I can't recall.
Anyway, it is/ was a very nice thing, added value to the item in a really tangible way through the extra content, and there was a number too, albeit of a very large set of numbers, if that's what floats one's boat. I'd certainly rather have that than just a number... :-)
It was a pity that that wasn't continued for the other colourizations.