He probably didn't know how to sharpen it...
I've been tinkering with the idea of putting a Doan MFS in the stone pocket. I can fit it in this sheath and close the flap, but it's pretty tight.I have a fresh, untreated sheath that I can wet mold and stretch the pocket a little. The other option is to trim some of the magnesium off the block. A small diamond plate like the Eze-lap fishhook sharpener would replace the issue stone.I would coat the MFS in varnish or fingernail polish...I've experienced corrosion on them when stored in the pocket of other leather sheaths.
That's an interesting knife as well Dunc. Are the extensions on each side of the handle quick-release activators?