As you noted the KAC parts are worth some money because KAC. How much? Couldn’t tell you but since they are long out of production pieces, they could be worth a few hundred or maybe not. The gun itself is nice, money went into it for sure but WC tend to cost more for the name rather than the sum of its parts. That is money you just won’t get back out of it unless you find just the right buyer. Honestly if it were mine, I’d keep it. They just don’t make them like that anymore. The other option would be to toss it up on Gunbroker and see where it lands. I’d be surprised if you got more than $800 for it though. A few things I never liked about the WC guns is that they were built off express 870s. In later production that meant things like mim parts, and cheaper dog carrier follower springs. Their applied finish is okay but in my opinion it is closer to a duracoat rather than a Cerakote and they spray the entire gun, including the action bars. The set up looks great but for the original cost of that set up which was probably around $1,800-$2,000, it is a bit of a rip off. Especially now days when that kind of money puts you into something like a Beretta 1301, A300UP or a used Benelli M4 which is a whole other class of shotgun that is better in every measurable way over a pump action 870. The 870 is a great shotgun at $600. At $2,000 it is lipstick on a pig.