JC,
It is a full octagon barrel.
I agree that the only African models I have seen - in pictures mind you, never held one - have had a smooth stock contour up to the tip which is normally a schnabel of some sort. There is one shown in Speed's book with a tip that just curves up to the barrel though too.
Mauser did show an illustration in their catalog of an African rifle with a "double" schnabel - the first being about five inches behind the front sling swivel pretty much like this rifle.