Hi Hacksaw,
Because the Marlin Papoose is a rimfire (not a centrefire) and the barrel was factory made in the short length is is not classed as a restricted firearm in Canada.  You do still need a normal Possession/Acqusition Licence to purchase it.
I mail-ordered mine from SIR in Winnipeg 
http://www.sirmailorder.ca/show_prod.php...c867c0801fd8e36Mike