Canada Admiral Imperf Proofs

Hi,
I am new to the forum and quite new to the world of collecting stamps.
but I have started collecting WAR STAMP not just from Canada but all Commonwealth countries that issued WAR STAMP or WAR TAX stamps for World War 1.
I acquired a large album of Canadian stamps through auction a few weeks ago as there was a large amount of Canadian War tax stamps in the album, I have started slowly going through its contents and found this stamp and not sure if it is correct or not.
it look like it has no perforations, I can find ones with just horizontal or vertical but cant find this one.
could anyone tell me the Stanley Gibbons number for this stamp or the Scott number as I have not been able to find it.
it would be great if someone knows the Stanley Gibbons number as that is my main reference book in the UK.
Many Thanks
Andy

Looks to me like it's had the perfs trimmed off on left and right. You can see portions of the holes left.