Dan, this is a repeat of the response I posted in the Spencer forum here ...
As a Model 1865 Spencer located in Canada, there is a more than passing chance this carbine might be one of the Spencers acquired for militia service by the United Province of Upper & Lower Canada (i.e. pre-Confederation Canada), along with other metallic-cartridge breechloaders, in response to the Fenian Raids of 1866-70.
In 1866, the Province of Canada bought 1,300 M'1865 Spencer carbines, while the British War Department bought 1,000 M'1865 Spencer carbines and 2,000 M'1865 Spencer rifles, which were loaned (and eventually transferred outright) to Canada.(Other breechloading acquisitions were 3,000 Peabody rifles and 1,000 Starr carbines, both of which were single-shot.
A Company of the Queen's Own Rifles of Toronto, armed with Spencer rifles and carbines -

In October of 1870, 100 Spencer carbines (along with 250 Peabody rifles) were shipped by the Dominion Militia Department to the Fort Garry Stores for service in "the North West Territories" (i.e what became Manitoba, Saskatchewan and Alberta.) Apparently, it was from these Stores that Spencer carbines were issued to the thirty Métis men hired as armed escort and scouts for the British contingent of the Boundary Commission surveying and marking the 49th Parallel west to the Continental Divide in 1872 and 1873. These men were permitted to retain their carbines following their service.
