The firm I work for had/have (unsure if we've still retained that exact one! Ill have a look on Monday), it a Jones and Shipman 540 surface grinder with the old company name on a little tag on the back of the machine with the old company name of Diagrit grinding company.
Unsure of the exact reason why a tag was placed on it, the fact that we still have it, were never machinery dealers, and Jones and Shipman being a British based company would indicate other uses to what has been said above. (I could be wrong!)
The picture above has a number 19 on the tag. The tag on our 540, I am unsure whether it has any numbers on it but could these tags been works machine numbers. I know all current grinding machines have a little plastic disc with a number which is to do with coolant records, but these do not have the company name.
Hope that is of any useful information
William