Why did I not look in my users handbook No. 12258?
Drawings do indeed show the sling with those type of hooks. Shows both types, army and Marines. Yours looks like the Marines one. Both types require special eyelets and mounts to fit to the rifle, look quite complicated. Also required lanyards and muzzle covers. I have a parts book somewhere, not sure if it included the artic slings though.
Army sling states made up of two, L2A1 and a L3A1.
Marines, L4A1
Hope of some help. Book quite thick and wont open up to scan.