Very nice hat, Jack. Reminds me of Brents' Serikon in its style. My guess is its a bit more modern hat; seventies perhaps.My contribution to this bevy of beautiful Borsas (I have this thing for using alliteration when I can ) This piece is called "Biver" which, if I may take poetic license by assuming it means "Beaver." Not certain of the approximate dates of production (I'll leave that up to to pros like you!) However, it is a Taupe color, much lighter in weight than it appears, with a stretched brim length of 3 1/4 inches, material covered leather sweat, and oh, those gills! Matches well with my vintage olive green Canali Alpaca wool overcoat.
On the noggin...