Hi Sean and group, I have four 56s in my garage, two from widely spaced parts of the US with undoubted, original delivery mirrors (one, the Windser Dad bought new). The 2 New Yorkers are identical, My Dad's and the 300B are slightly different from those and each other, but maintain the same "feel" if not exact dimensions. So what is correct? All of them I suspect. At any rate, you can buy from Jay Fisher {732) 388-6442 what are reputed to be correct mirrors. He advertises in the News- Flight. All the best 300ing, Phil Irish PS you can see the mirror on my red B in Nashville, Y'all come !!