Time signatures--any notated music for that matter--is at best a rough approximation of what's actually sung or played. Since the folk have traditionally been free with rhythm, beat and melody, any assigned time signature is best taken with several grains of salt. Ye Mar'ners All is often written down in 5/4 time; often in 4/4. The transcription I received of (When We Go)Rolling Home is in 7/8 time; to my ear it's generally sung in 4/4 with some held notes.

Whatever works.

Moondog, by the way, was well-known for playing with unusual meters.