I found the mill on Craigslist. I went and took a look and it was in decent shape. The first thing I did when I got it home was to remove all the stock electronics and clean it up.
I'm not sure what the difference is between the 2400 and 2100. The 2100 doesn't have the built in oiler that the 2400 has. Other than that, not sure.
I'm going to post some pictures. A note on these pictures - while they are reasonably good size pictures you can click the link below each picture to go to the full size image. BEWARE: The full size images are 12MP images and range in size from 2MB to 6MB.
This is a view of the base of the machine with x and y axes removed. They look like hand scraped ways.