I am not aware of any data base of Williams locomotives. As for the year it was manufactured, that is a tough question as well. They were made for many years starting in the late 1980's to best of my knowledge all the way through ownership by Bachmann. There isn't a lot of difference between the models. Some of the earlier ones had Ott sound systems, but otherwise the parts are pretty universal. I don't recall if the PA goes far enough back to have the motors without flywheels like the early FP45s, the SD45 and a few others.
Not sure I was helpful, but hopefully a little?