We play it with one more chord than Seany, probably because we grew up playing 70's rock and roll in various gargages:
[G] Step we gaily [Em] on we go
[C] Heel to heel and [D] toe to toe
[G] Arm in arm and [Em] row for row
[C] All for Mari's [D]wedding
and same for verses; moves nicely into "Hey Baby" and "Blue Moon"