Herb and Doubs,
About the Crown/N, you are both right. The difference is in the detail of the crown. The 1950 Suhl crown is different in detail from the 1906 Imperial Commercial proof crown.
Here is the comparison, the crown on the left is from the gun pictured above and has the characteristics of the Suhl corwn; the one on the right is an Alphabet Commercial.
Its a bit difficult to see the pertinent details here (the N is overstamped and obscures the bottom of the crown a bit), note particularly the shape and height of the "petals" that form the vertical parts of the Suhl proof, as opposed to the more facet-like parts of the Imperial crown.
Costanzo shows the differences much more clearly on pages 164 and 201.
--Dwight