I've seen a couple of 'SA' marked green leather M39 style slings for sale on the Intertron over the past two years. Should've bought one but I couldn't talk the seller into shipping outside of the US. I'd assumed these were meant for the M27 instead of the M39 - but as we all know, whatever sling was available went on whatever rifle was available. I've seen a 1943 vintage photo of a Finnish soldier with a Carcano sling on his M39. I originally thought it was a Swedish Mauser sling, but they don't fit.