Help w info about Franz Poriska, Wein - 16ga x 11mm Cape Gun.

Not sure if this is the correct forum for this, but here goes ...

I recently acquired another Cape Gun. This makes number 6 in my collection. Although I just purchased it from a private party, I found it was listed for sale in the Rock Island Auction back in September of 2010. The only info I have is what was shown in that listing. (see pic) There are no caliber marks or proof marks and no serial number or assembly numbers. The only markings are on the barrels and both locks. I'd be interested to know the place and date of manufacture if possible.

A modern 450 bpe case is too large and will not fit into the chamber - it only goes in approx. 1 inch. Both the rifle and the shotgun chambers and bores are "mirror-bright" from muzzle to breech. It looks to be seldom fired, if at all.

Any additional info would be greatly appreciated.