The big whoop about these bikes is that they are considered historic, as the first production mountain bikes. There's even an
'82 Stumpjumper in the Smithsonian.
These first-year Stumpjumpers seem fairly well-documented. Some ads and brochures are up on this page. There are excellent timelines and specs on the First Flight website. And there's now a book called Stumpjumper: 25 years of Mountain Biking, by Mark Reidy.
Most agree on this story about '82 Stumpjumpers: they were copied from 3 different sizes of '81 Ritchey MountainBikes brought by Mike Sinyard to Japan. The framesets were built by Toyo, and there were only 500 bikes made from 10/81 through 1982. They cost $750, or half of the price of a Ritchey. The wheels were built by Wheelsmith but otherwise the bikes were imported as a loose pile of parts in a box, which the shop would have to spend hours assembling.
Part of what makes these interesting is that mountain bikes preceded mountain bike parts. So these came with stuff borrowed from BMX, French touring, and motorcycles. Also there were some mini-generations of this bike. The earliest (sometimes called 1981s) have different decals and sometimes a cast fork crown before the 'biplane'-type appeared. And the latest '82 frames are lugged.
Some other notable production bikes that year were the Schwinn King Sting and Univega Alpina Sport :
