Speaking from undergraduate life in the Cornell Big Red Marching Band (and a few sessions with the Leland Stanford Junior (PAUSE!) University marching Band), I can give you a definite answer:
Yes AND no.

There's many that were consciously writen and consciously written down before their authors got forgotten. (see http://www.rso.cornell.edu/marchingband/fight.html although interestingly enough I thought it was Phil who wrote NCFS not Prof Stith...folk process?)

But there's MANY many more that aren't. But they tend to be a bit off-color, to say the least.

To the tune of "Give my regards to Broadway" (via the Cornell Fight Song "Give my regards to Davy"), there was a ...charming? little ditty that started out "We are a bunch of bastards, we are the scum of the earth" and got worse from there."

Folk yes. Clean enough for polite musical conversation, no.

;)

--guess who