See back cover Details October-December on this "Canada's First" item.
The item description is unclear to me. So I called Philatelic Centre this morning and asked what "imperforate between rows" means. After chatting I'm thinking this means that each stamp is separate on the sheet with "perfs" on top and bottom but none on the sides - as a coil would appear. The stamps are all peel and stick and individual.

Anyone think this means something else?