As the television commercial jingle says, "Ace is the place...."
The guys at DaewooRifleParts.com forums
can tell you Exactly what you need and are quite supportive of the 'woo.
One thing though... you won't be able to use an AR grip; only a replacement Daewoo K2 or equivalent.
Truth be told, I think I like the adjustable M4 stock even better than the standard, If I weren't intent on keeping mine original, I'd switch as well.