Cool video. He did a nice job on the case. Connectors on the ribbon cables still looked filthy, and getting on a circuit board with a soldering gun.
The guys that do my amp restorations and repairs don't do it that way.
I did not realize those amps used TO-3 output devices -couldn't read the actual part number. But in general those are getting harder and harder to get reliably and are so commonly counterfeited.
I also would have replaced more electrolytics out of habit as well as refreshed some of those rotted away cardboard insulated pads under the circuit boards.
Luckily it looks like the gaping burn-out holes in that circuit board didn't affect operation, unless the amp he's playing at the end is another unit altogether! I've seen similar tricks used in other machine and engine restoration videos (It's all about the clicks and the views, not about accuracy)