They didn’t come with a sling, and I don’t think Savage was selling a sling at that time.
Seems odd they'd produce a rifle sling ready without the sling.
Mine has a leather sling of some sort on it. Hafta look closer for markings sometime.
Did Savage supply slings on any other rifles? Military? RS?
Oops.. have to correct myself. At the end of the 20's they listed a Kerr adjustable sling in the Component Parts catalog, but not earlier in catalogs or component parts list. I did however just find on the 1923'ish pricelist that it lists a Kerr adjustable sling. So they might have been selling that sling as early as 1919, but it would have been an accessory.
Here's the catalogued picture.
PS: They also listed a more standard hunting style strap with sling hooks for model 99's and 1920's.