WD40 is actually really bad for stocks, water displacement 40, removes what little moisture there is from the surface of the wood and can cause it to shrink and the wood grains to separate and start to splinter.
I use linseed oil on all my milsurps and it does seal in what little moisture you want, causes the wood to swell as it absorbs the oil and keeps any outside moisture out, preserving your stock. it gets rid of the color contrasts of the scratches but does not get rid of them...
my brother calls it 'sealing in the ugly' whenever I linseed my stocks