I would imagine that they are from a pack of CD-Rs and numbered sequentially.
I received mine as well. Seems completely legal, despite being cd-r.
But to follow up on the numbers: my number is 6K863C0130680
Looking back in the previous replies, we so far have:
6K863C0125180 Crayon
6K863C0127880 yseilys
6K863C0127980 Brad
6K863C0129180 God, Part II
6K863C0130680 sleus
and if I remove the last two digits (80, being the lenght of the cd-r) and the firts 8 characters which are identical for every copy so far, that leaves us with the following sequence
251 Crayon
278 yseilys
279 Brad
291 God, Part II
306 sleus
I'm trying to figure out how many copies were printed. So the question is, where did they start? number 001? Or perhaps 200?
And where does it end, 306 seems very unlikely to be the very last copy.
Looking at the numbers at least 55 copies were printed so it seems safe to say that at least 100 copies exist.
any thoughts?