All signs point to "SELL". These go for great money. The factory case jumps the price significantly, mags prices are stupid. I've never even seen the factory leather. Do it like this:
1) Gun/holster/1 spare mag pouch with spares.
2) Mag pouch with spares.
3) separate listings for the other mags.
These 3 listings should bring you the best buy price for the whole thing. Do not list it all that way, you will get less. Do not put a Buy It Now price on the listings. DO NOT accept offfers to end any of the listings early, unless you REALLY know the market that is a bad idea.