Jerry, I've looked at this request several times, and wanted to respond, but the truth is, I don't have much in the way of definitive I can add to the discussion. The "G"/"HG" designations from what I can tell are interchangeable. In other words, they don't refer to two different models of Hohner guitars. The only Arbor series Hohner I've owned or even seen in person is my G-940. But even though the model designation doesn't begin with "HG," mine is clearly from the Arbor series. I bought it new here in Corpus Christi, TX in the spring of 1983, April, I think. But that doesn't necessarily tell me when it was made. I have no idea how long that guitar had been hanging around in the local shop. The store owner was definitely trying to steer me toward it, maybe because he'd had it a while and it just wasn't getting attention because it wasn't a Martin or Gibson. At the time, I wasn't aware of the Arbor series Hohners. But although it may have been self-serving on his part to hard sell that Hohner, I'm certainly glad I did. It's been almost 35 years ago now, but if memory serves, I don't think I looked at another guitar after getting that one in my hands. But I digress. All of that to say that I don't know exactly how old mine is; I just know when I bought it. And I know that it's an Arbor series Hohner, despite not having the "HG" model # designation, and that it was made in Japan. Here are some close-up pics of inside the soundhole, starting with one I just took... My Hohner G-940, Close-up Inside The Soundhole - 02-19-2018 by LGOberean posted Feb 19, 2018 at 10:27 AM My Hohner G-940, in the soundhole -1 by LGOberean posted Aug 21, 2013 at 10:09 AM My Hohner G-940, in the soundhole - 2 by LGOberean posted Aug 21, 2013 at 10:09 AM In that third pic, one of the braces on the bass side has stamped on it "S13." I don't know what that means, though.