Sad news to report. During first period of running in amp, it blew a fuse after about 6 hours of playing and since this is test mule with Antek 3218, I only put in 2.5A fuse (2.5x120V = 300W). No big deal. I changed to 3A fuse and it was playing again for about 1 hour and blew again. Changed to 4A fuse and either I wasn't waiting long enough to drain caps or it just was already on way to Ge-drekland. Went back to front end (FE) and output section (OS) testing, FE was still fine but OS was 50% THD. I changed active parts (817, 385, 139/140) thinking the mosfets were sturdy fellows but still no good. Pulled IRF9510 and put on tester, tested ok so only conclusion was Ge. I swapped 22R back in for R122, plugged 2SA1943 and everything is good again in that channel. Has to be 2N1099 slowly turned itself into a jumper wire. Id was set at 1A but after it went bad, on the bench supply, it was pulling 2A (limiter) on both rails.
I will take this opportunity to test 2N277 (Delco) as I found datasheet which is different spec from the Motorola 2N277 and looks like it might survive.
Thanks for posting the datasheets. It's interesting that the Delco gives a max junction-to-case thermal resistance of 0.8C/W while the Motorola one is given as max 0.5C/W. And it seems the Motorola one gives a higher max junction operating temp as well.