Military issue bugles will have abroad arrow mark on them, the Canadian version in this case and usually a date as well on the outside. The number 31 is probably a part or batch number or perhaps that of the individual craftsman.
Not military issue IMO. Hard to date, it could be C. WWI.
Whatever its just an opinion.
For more information on military bugles have a look on the 'Canadian Anglo-Boer War Museum' website. There are examples from the Boer war and later. It will show you the markings you can expect to find on a genuine military piece. There is also a good section on fake bugles too.
Books published to date... 'Belfast Diaries: A Gunner In Northern Ireland'... 'A Tough Nut To Crack - Andersonstown'... 'An Accrington Pal: The Diaries of Pte Jack Smallshaw, September 1914 To March 1919'.