REALLY RARE COUESNON SAXIE, PROTOTYPE? OTHER?

Description

Rare find! It seems to be a saxie made by Couesnon Paris but there is no stamp.
Compare to other model, there are more holes.
So is it a saxie, a prototype or other? I'm very interested if you have more informations.
Sold as is, unfinished,without mouthpiece or case.
Please see my other instruments for sale, I combine shipping!
More details and pics on ask.
Package is heavy so shipping cost are:
Europe:
All around the world: