A kind lady passed her father's accordion on to me, and told me some of his story. Her dad died in 1975, and clearly this accordion means a lot to her, even though it's in pretty rough shape. I'm guessing it dates from the early 1950s. Are there any aspects of accordion design and construction that are particular to that era? I was surprised to find it has a low A in the bass - none of my other accordions has that. It's a 4 voice with MMM, the concert switch is two Ms, while the musette is all three. First time I've seen a "concert" switch. I have yet to open it up; I'll do that during the Christmas holidays. Surprisingly, no visible bellows wear, despite the condition. There is nothing to be found on the back, except for "Made in Italy". Any info is much appreciated.