Good luck.
Next time you speak to someone, ask for a replacement stock for a particular Mossberg model number. That seems to be the best way to accomplish what you're trying to do. Take a look through the models in this link and reference the model number that has the length and color stock you are looking for, item#27220, etc...
http://www.mossberg.com/rifle-calibers/243-win
Oh and by the way, Mossberg is the parent company and manufacturer. Their customer service and fulfillment departments are based in the Maverick Arms facility in Eagle Pass Texas...