I think it was in it, but the copyright is 1918! OWALW was made up from "bits left over" to a large extent.
Here's that missing verse:
4. Little Private Patrick Shaw He was a prisoner of war Till a Hun with a gun Called him "pig-dog" for fun. Then Paddy punched him on the jaw. Right across the barb-wire fence The German dropped, then, dear, oh, dear! All the wire gave way, And Paddy yelled "Hooray!" As he ran for the Dutch frontier. CHORUS