Brunswick Hoppe shaft?

[blackwidows]

I purchased the shaft from Ebay a couple of years ago as a hoppe shaft. I am curious if anyone has seen one with these markings. It appears to have an S stamped on the end by the insert. Also I am wondering if this appears to be an ivory ferrule? It does have some grain to it. Any help would be appreciated.
Thanks
Blackwidows

 

[fsarfino]

just a wild guess "s" means spare

 

[Kobachi]

either Ivory or...

buckhorn? I thought I heard somewhere that they used buckhorn at one time, looks just like the ivory. Maybe I'm crazy, but I think I heard that somewhere. As for the "S", the previous poster, spare, or who knows, maybe it's just S for shaft wood, I'm curious too...