That is the very rare HC-85, which is exactly what you described. A four EL34 HC-30. They made very few of them. I had one a few years ago. Great amp but extremely heavy. Looks like it's in a combo, which hurts my back just thinking about.
Six years too late, but it seemed like it was worth the zombie thread to have it answered.
Matchless amps are works of art. That's hours of handwiring. Notice the bare wire on all components have been covered with tubing. Even with that artistic spaghetti, it's resistant to interference, making it run dead silent.
I've owned an early gray DC-30 and two Chieftain 212's. I still have my Sampson era 1997 Chieftain. For clean and pushed clean, this amp will stomp on a lot of good amps.