The story is known to be inaccurate in technical detail¹, so it's not impossible that it's inaccurate in social detail as well. There's some LGP-30 code on Bitsavers including scanned coding forms, and the ones initialled ‘MK’ are not notably different in level of commentary from the others.
Ah, I didn't know that. As for the code on Bitsavers, I'll have to check that out. I should have expected there would be something there - Al is a gem (albeit a cranky old gem), and I wish he'd get more love.
¹ https://news.ycombinator.com/item?id=20489273