SWTPC board

I'm starting to make progress in going through the carload of stuff I rescued earlier. For starters: One of the things I found in the heap was a SWTPC CPU board. I know nothing about them, but it looked interesting enough to be worth saving However, the board's different to the one at: http://www.computercloset.org/SWTPC6800.htm This one has 5 larger IC sockets along the top edge, the leftmost of which is populated. there are two 7805 regulators toward the centre of the board at the bottom. Bus is 50 pins, just like the card in the above photo - SW-50 I guess. There was no sign of a case for the board, backplane, or any other cards though. Anyone know what the different board variations are? This one says "MP-A2" in the top right corner along with a copyright symbol. Build date looks to be mid-to-late 1977. On the back, written in pencil, is "MRC original board" (which probably doesn't mean anything to anyone!) cheers Jules