Racks ?

I've been offered 2 castored racks by the owner of the place I am using temporarily for storage, which were abandoned by a previous occupant. They are about 5' high by 24'' wide with lockable front and rear doors. One of the rear doors had been forced open and I only got a quick glance inside. I made out a micropolis(IIRC) mfr. label on one module and a large "PDP 4800" stencil on another one which looked like a PSU. There were about 20 DB25 cables connected to one of the modules. I'm a complete novice when it comes to mini's, and due to storage space limitations plus that I would also have to remove them when I vacate my locker I've been reluctant to take them. Anyone have any idea on what they might be ? I realize this is not much info and will be looking at them again when I have a flashlight and a means of forcing open a front door panel. ciao larry