The earliest known records of Hawken rifles date back to the early 1820’s. Hawken rifles were originally of Flintlock design muzzleloaders, however Hawken rifles were also made in the newer (and preferred) Percussion Cap lock design starting around 1835.
The fact that your heirloom rifle is a Percussion cap rifle has no bearing on the fact that it DOES qualify as an Antique under Canadian Firearms Act & Regulations simply because it was built BEFORE 1898. As long as you can prove that it was in fact made before 1898, the RCMP can provide you with a FRT (Firearms Reference Table) Letter which will state that it is an Antique.
Owning this particular firearm would be an honour in any family and would not require a Canadian Firearms License (PAL) in order to purchase own or use it. Fun Fact!