Very nicely finished indeed. Does the stock have a matching number to the rest of the rifle? If you haven't looked there should be a number stamped into the wood, in the barrel channel. The duffle cut stock can be repaired, and hidden by the lower band. I would suggest repairing the stock over finding another one if the stock does have a matching number.
Most repaired duffle cut stocks I have seen use a combination of 2 metal rods and heavy duty glue. Two holes are drilled in both sections of the stock, about an inch, and then slightly larger diameter steel rods are press-fit into the lower section. Next add glue to both stock sections and press fit the small upper section onto the lower. Once dry, carefully sand off excess glue and reassemble. Since your Kriegsmodell rifle's barrel bands are held on with wood screws, you'd want to drill one hole about where the cleaning rod hole would be. The tighter fit of the steel rod into each section of the stock, the better.
Handguards can be had for about $25 or so. Check the following link for one that most closely matches your stock color. The stock is laminated, so get a laminated handguard to go with it (as opposed to hardwood). Even though it won't match the rifle, getting a handguard will probably make it easier to sell if you decide to do so. An original sling would also be a nice addition.
http://www.palmbeachparts.com/Mauser_K98_Parts.php
Bore condition will of course affect value. Any pitting from corrosive ammo? I currently have 3 K98s (1939 S/243, byf 43, and byf 44), feel free to PM me if you need more info.
-Eric