Rattle can that shit with good rustoleum 2x paint. Sand it down good, clean it really good, paint, then matte clear. I've done a couple rifles and shot the hell out of them. I'm talking thousands of rounds of positional practice between 223 and 22lr, both held up great.
I'm not saying cerakote isn't better, cause my match rifles have been cerakote. But if it's just a plastic stock why spend the money on cerakote. Use that money to buy a better stock/chassis