The butt stock appears to be the same as the BC and Target, the forend appears to be shorter tho, possibly the same as the older schable forend, but of checkered walnut. I don't see them changing the position of the forend stud on the carbine, the BC and Target forends work fine on Handi barrels and vice versa.
As far as availability, I doubt very much they'll be available before the production run of the complete rifles as all will be used for that purpose before they sell the components, a call to Jenn would answer that question, I'm sure. She did tell me that the sights won't be available for quite a while, the forend will probably be the same.
Tim