Thanks for your interesting and very valuable input, my friend.
I knew that some protos had a see through case back, I didn't know ALL the protos had it, and specially this Mare...
But as always, when you don't know ...Dédé knows!
As for your wishes to get a 47 mm Mare, I'm in with you!
At least I will finally have an untouched smooth bezel!

Best, my friend.
Nicolas