http://www.project1999.org/forums/sh...ad.php?t=43779
It sounds as though this has been discussed many times in the past.
Most of the sites listed have it early October or August of 2000, which as far as the wiki's timeline is concerned, is 1-2 months after the release of the epics, though they might have been released simultaneously. If we haven't yet reached the tradeskill patch then my apologies, this isn't a bug, but it seems like it came with the epics.
However, if it shouldn't be in the game, a bug still exists, but the items described in To Dye and Stain should be removed from said vendors, including the book itself, until such time as they are supposed to be in the game.