Wooden M1 carbine training rifle

The auction house advertised it as an M1 carbine "training" rifle, with only four photos in the listing. It was the C-tipped sling that caught my eye. I placed the minimum bid and with no other bidders, I won the carbine. The sling turned out to be in like new condition, olive drab, and un-marked. I believe the butt plate is late Winchester with two dots on the bottom row. The oiler is simply a length of wooden dowel painted grey. In the sling-cut the mark is a large letter J which I think makes it a replacement stock. There are no cartouches or other marks on the stock or grip. Notice in the photos that the stock has been cut its entire length, almost down to the GI barrel band spring, and that there is a 3/8" thick strip of wood sandwiched between it and the deep groove handguard. Metal parts beside the butt plate include the rear sight, the imitation type II barrel band swivel and a nut and bolt through the stock above the wooden trigger housing. There is no evidence of this toy ever having a trigger and all wooden parts are solidly glued together. Notice the magazine size difference in the last photo. This "training" rifle is now a wall hanger in my shop but would make a great conversation piece on any gun show table.
Who made this carbine and when? Any thoughts?

Does anyone have a wooden Garand trainer?