It's a Japanese 15 clone. Hard to date those. All of them weer post WWII. Link to more info
http://www.quiltingboard.com/picture...p-t164361.html
and here is one I cleaned up - more info there too
http://www.quiltingboard.com/vintage...r-t169127.html
Those are my favorite for free motion. Those will sew through anything. Muv's video is fab. There is a link toward the end of the thread.