"Rolling in [on] the Ryegrass" is in O'Neill's 1001 Gems (#766), so it stretches my personal credulity a bit to think that either O'Keeffe or Reavey were the composers unless it's like one of those old Star Treks where the Enterprise goes into a time warp and the crew winds up in San Francisco c.1860 and Spock has problems hiding his pointy ears. I mean, the parallels should be pretty darned obvious to everybody...?
Which reminds me: According to my sources (who for obvious reasons wish to remain anonymous), "Ryegrass" was actually composed by Ali Ahmed bin Waleed, a prominent Chicago Islamic cittern player who was a close personal friend of Chief O'Neill. Other tunes he is alleged to have composed include "Silver Spear of the Brave Mujihadeen", "The Decree of Death by Stoning against the Maid behind the Bar", "The 'Al-Qaimi b'tkaaliyeh dzhazh u kesh bil Shams" Jig, "More Power to your Elbow, o Assassin of Infidel Dogs!", "Mustafa with the Queer Thing", and "When Sick Is It Hashish You Want?"
"Ali writes great tunes," the Chief is reported as saying, "but we have to do something with those names or we'll never get them into the book." Reportedly the faithful Sgt. James "No Relation" O'Neill was given the task of editing the names of Ali's contributions, and the rest (as they say) is history.
Yours for as much accuracy as you can safely deal with