This is what I came up with. Not sure on the number. From what I read here serial numbers were not a priority of W&G. What I also look for is a number on the bottom side of the machine since the number on the top does not seem to show any relevance.
http://ismacs.net/willcoxandgibbs/im...ing-guide.html. This will at least give you a bit of info on the machine. Sorry I couldn't be of more help.