You lucky guys – I should have imagined (in some way) that with the kind of culture you always had associated with the b.d. in France, there might have been a nurtured collecting base for original non-french comics as well.
Unfortunately it’s not just a matter of SA: the collecting base in Italy is almost non-existent for all ages: people are mostly just not prone to appreciate things in their original language and form. That is why I find wonderful that you can dig out GA and SA comic books from France.
OA is another matter: I have an acquaintance which has several Sienkiewicz pages (even some painted ones from "Love and War") and there are many OA collectors here as well.
As for the Cap: there is to say that rare and super-rare does not necessarily coincide with "sought after": value is often "impossible" to determine, or better it should be determined at one’s best upon request as well.
For example, this is one of a few Superman "apocryphal" italian comics, which came out as a follow up of the very first story published here (very likely unauthorized) in 1939. They are super-rare and I would not know how to price it – I just picked it as the occasion arised, but they are pretty much "priceless".