Your bag was original to Models 516, 517 & 518. The 513 & 514 has the same, new angular logo but the K and Y extend in a point down the length of the bag. With the Model 519, the bag was the same except that it had a "speckled" gray pattern and the same bag was used for the 519, 560 & 561.
Since the bag is solid gray and not speckle tone, I would venture to say that it is off of a 516. I don't believe the speckle tone bag was available until 1957 or maybe even 1958. The emptor fits a 516 and later.