Another M68K Qbus cpu!

A good day at the auction!. I picked up a 11/73 in a BA11-S chassis and a couple of IBM 5150's that I mainly want for the MFM hard drives I also picked up another M68K qbus cpu in a BA11-MA chassis. This one also has the eprom for the MACSBUG firmware monitor. Thanks to the IS pdf on AL Kossow's site I know, with the unix eproms, these are capable of booting a M68K version of 4.3BSD. (providing of course I could find a copy of the OS or even compile the source). But what OS can these boards run with the MACSBUG firmware? I now have two of these boards but I have yet to find out what OS they run? Anybody know?? These machines were probably used for lab equipment as they also have an Extrel sticker on the cpu and an unknown Extrel branded qbus board with two 20 pin connectors, There is very little printed on the Extrel Qbus board for identification, my guess is that they are some sort of serial board, an i/o board or even a floppy disk controller, but the lack of any identifiable controller chip make it hard..any guesses?? Cheers Tom