Doesn't matter, you'd only get £100 to £130 max for it. You don't buy airsoft guns to break even or make profit, you buy them to have fun with them, then when you fancy a change you sell it for a low price to aid funding another gun or swap it. You'd get nothing but £100 guns offered for your CM16 as a trade, it's pretty much the baby blocks which everyone starts with. Nobody would pay access of £130 if you're lucky. Heck, I'd only pay £120, worth about £100. Nobody cares about a fancy stock on it, a stocks a stock, nobody would pay more than it retails for unless you have some "ultra custom" P* build or just a load of magazines, upgrades, batteries etc etc.