According to the dates of manufacture in the back of the Blue Book it shows my gun as a 1937 model. It has a 20" barrel so that would make it a carbine wouldn't it? I don't know much, hardly anything in fact, about M63's so I'm just getting this information from the blue book.
I am going to try to sell this gun and was just wondering if the "A" made it something rare. I know if you find a Pre-64 M70 with a letter after the number it generally means that it was duplicate serial number and commands a little premium.
