Dont know it this would apply, but when I re-handle an ax for instance, Ive learned that if you use a grinding wheel to remove that last bit of wood, and get the metal wedges even, it burns the end grain of the handle. This seems to be a benefit, (I live on the Gulf coast...Think humidity, and wet ground) at keepin the handle from swellin and contractin, causing a loose handle. Seems to 'waterprof' it some what. The wood seems to be harder there also. Kind of like fire hardening a sharp stick for a spear!
Just my $.02s worth, but the blackened end grain would probably look almost like a butt plate!