I tried dinner at a nice restaurant and flowers but that got me nowhere.
I had always assumed it was an '85 because the stem that came with it had an "85" stamped on it. I also know this wasn't the length of the stem, because it also had an "80" stamped on the other side and when I measured it the two numbers matched. I could not find any dates on the hubs. Then I started looking around online and the few Prestiges I saw that were claimed as '85s looked different/newer than mine. I found a couple that looked exactly like mine, but with no mention of the model year. Next I read that sometimes DiaCompe parts have the date stamped on them so I checked the brakes. "0285M" is the only number I see resembling a date. More evidence pointing toward it being an '85? Yet the graphics are quite different from others I've seen that are supposed to be that year. Also, I thought most bike companies had quit routing the shifter cables above the bb by then. But it also came with an oval inner chainring, although I don't know if that is an original piece. The serial number on the bottom bracket shell is WE 03492.
Here are some detail pictures:
http://img.photobucket.com/albums/v2..._8857small.jpg
http://img.photobucket.com/albums/v2..._8856small.jpg
http://img.photobucket.com/albums/v2..._8854small.jpg
http://img.photobucket.com/albums/v2..._8853small.jpg
http://img.photobucket.com/albums/v2..._8852small.jpg
http://img.photobucket.com/albums/v2..._8851small.jpg
http://img.photobucket.com/albums/v2..._8850small.jpg
http://img.photobucket.com/albums/v2..._8848small.jpg
http://img.photobucket.com/albums/v2..._8847small.jpg
http://img.photobucket.com/albums/v2..._8846small.jpg
http://img.photobucket.com/albums/v2..._8845small.jpg
http://img.photobucket.com/albums/v2..._8844small.jpg
http://img.photobucket.com/albums/v2..._8842small.jpg
http://img.photobucket.com/albums/v2..._8841small.jpg
http://img.photobucket.com/albums/v2..._8839small.jpg
I'll admit that my internet searching abilities are not the best, but so far I haven't turned up much information on the Prestige. I'm not even sure how it ranks in Nishiki's line.