As much as I regret it, I can't offer any information about that Coticule. Vintage Coticules can come from any former mine. There are 3 main Coticule deposits: The Ottré-Regne" deposit (Ardennes owns a mine at Ragné, but currently does no extraction over there), the Salmchateau-Ol'Preu deposit (Ardennes currently quarries at Ol'Preu), and the Sart deposit. Thee deposits are several km long. There were many mines in the past, all tapping into one of these 3 deposits. I only have information about the morphology of the stones that come from Ol'Preu location. Possibly, that information is more or less valid for that entire deposit, although some old source suggest that their was variation alongside one deposit. Anyway: without being able to even tell a mining location, I can't possible make any layer determination, even if I know what to look for in currently not mined layers like L'Allemande, Les Dados, Les Petas, La Rouge, etc...
In other words, your vintage Coticule could be one of many unknown possibilities. It's a dream of mine to start with a Coticule Gallery, more or less similar to the Vault, where we could line up as many vintage Coticules as possible, together with a test report (a standardized test needs to be developed, so every owner can run it on his specimen). It's the only way I see to allow for a possible future classification of vintage Coticules.