I've had several Zastava's over the years. I stripped every one of them and refinished with oil. Bedding the action will eliminate any movement which is usually a contributing factor in cracked stocks. I happen to have a Zastava stock on the bench right now that needs several more coats of oil to complete it. Some come with nicely figured wood but the cheesy stamped checkering and low quality varnish leave a lot to be desired. There are lots of options when it comes to aftermarket stocks so it's up to you as how much love you have for your rifle. I love my Mauser actions and for the price, the Zastava's are a bargain.
The manual that came with mine stated that it is a linseed oil finish, and that touchups could be done with linseed oil. I wiped mine down with menthol hydrate, and then applied tong oil directly to the stock. Great results. Regarding the checkering; I may get a tool and simply recut the checkering if I can find one the right pitch; sharpened up with an oil finish would add a lot to the looks.