It's not an A-2 jacket, it's a civilian A-2 style jacket very similar to the old Schott 674.
I won't guess how old it is, but for what it's worth, these sorts of jackets were popular for decades. (I bought a brand new Schott 674 in 1984.) Hopefully, one of our Buco experts will know more.
Not to say that it isn't a cool jacket... But the two-piece back, blended-fabric knits, double-entry pockets, snaps on the windflap, and missing spec label, throat hook, and collar snaps all mark it as not being a legit spec A-2.