Ganey,
not trying to argue, but can't the Do start at any root?
If the Do started at the C, yes, the "M" would be the 3, or the E.
Don't think too many accordions were built in LA in that key, but Quebec is a different animal.
Whatever the root is, wouldn't the 3 would be the Mi.
Still think this is a one-time spoof, since "joe" hasn't got back in the fray.
JB

Mais, methinks the mythical "M" must be muted.

Yes, technically, but in accordion terms, "Do" is C. If you order a set of reeds from Italy in the key of C, they come marked "Do." Key of D is marked "Re," and so on. I presume it is because middle C is the reference. I don't know. Maybe someone like Chris could answer that.