I have an old Buck fixed blade knife with the black resin handle. It has a hidden tang altho there is a pin at the end of the handle through the aluminum end cap (and tang?). Is it possible to replace the handle with a wood handle? I would think wood scales wouldn't work, but would need solid wood with the tang epoxied in place. Is that correct? How would one remove the existing handle? Who could do this kind of work? Thanks.

I have a few knives that have a solid piece of wood epoxied in place .You can also epoxy a decorative end cap in place .I would also recommend stabilized wood for durability.Not a big project.

The pin at the end off the knife should be the tang of the blade. The tang is peened over to form a rivet head. You will need to carefully grind the end off the tang until the pommel(end cap) comes off.
To replace the handle you take a solid piece of wood/bone/acrylic and drill it through. I usually wobble the bit to get the oval hole needed.
NorthCoast Knives has a decent tutorial http://www.northcoastknives.com NorthCoast
If you have any other questions you can PM me.