Yea, O-Fest is our translation of Germany's Marzenbier. I think they brewed it as summer was heating up, lagered it over summer, and broke it out for their fall celebrations.
Which, given the insane hot temps this summer, may be my plan next year.
And that profile is just my idea based on the style. As you hinted, I personally doubt Munich brewers are still "targeting" their native historical profiles these days. Now, they understand all these water chemistry issues, whereas back then they did not, and trial-n-errored their way to a brew/recipe that worked with water they could not change.