Call Ka-Bar directly. I talked to John Stitt about this at Blade Show and he says they have them, even the new sheath with the Molle strapping, at a VERY reasonable price. I think he said they were $9. I don't remember if that is the exact price he said or not but that is sticking in my mind so I think it is.
My sheath is the old style and doesn't have the Molle backing which makes mounting it onto my pack rather difficult so I am going to get the new sheath so it makes it easier.