Cutler-Hammer d120

I have a mill that want me to upgrade an old PLC. I can't find anything about it and the mill has nothing for me to look at (no manuals, drawings or program). I believe it is a Cutler-Hammer D120 PLC (but not 100% sure since I haven't been on-site yet).

It can't be much of a program but I was hoping to get an idea of what I'm stepping into.

Thanks,
Phil

I am not sure about the D120, the 100's were made by Toshiba. You may find manuals etc on the Toshiba support site under PLC>Legacy;
http://www.toshiba.com/ind/downloads_main.jsp