I'm the original owner. Where is the serial # located It is half open in back . It has a single channel. It is one unit (speaker+power amp). It's heavy. I love the tone it gives. It needs new pots or something because at higher volumes, it has some fuzzing or crackling on the attack and decay. It's fine at lower volumes.
NOTE from BeegAl - you can find the serial number on the chassis when looking at the amp from the rear. It should be on the plate attached to the chassis.