Peter that "N" in a shield is the Prague-Weipert 4th proof of semi-smokeless powder. Weipert, and the subsequent Brno facility, would have a "*" coupled with the Nitro type mark. The 1st proof was in 1925 as you noted and the weight is on the lower rib. In 1932 it was imported into Prague and passed thru the proofhouse. Then in 1965 there was some alteration and it once again passed thru the Prague proofhouse. There looks to be some difference in the weights(flat stamp could also be 1925 and lower rib 1965 stamp???). I haven't looked closely at the 2 stamps, but it might provide some insight as to the alteration. There is a mark forward on the left flat I can't tell what it is but there appears to be a "Crown" over "D" just ahead of the flats just before the "Choke" mark on the left flat. I assume the "17.2" was stamped in the 1965 effort but it could have been applied at the Prague proofhouse facility in 1932, but I don't know why.
Canvasback, I was checking my notes to see if Ingrid had noted what was on the medallion.
Kind Regards,
Raimey
rse
