However, here is a search engine result with a few links , as you know the guitar's details you'll get better results..
http://www.google.co.uk/search?hl=en&q=jackson++guitar+serial+number&meta=
Sounds like a bargain - you say she works fine? well, is she worth $250 to you ,that seems like the point to answer, whether she's a Jackson/a historic Jackson or not a Jackson at all:)
Good Luck.
Accuracy,you say? hmm interesting concept..