Several questions:
German/Austrian legal customs: As long as a paper like those shown shows an adress on top, in these cases a stamp, and is unsigned, it is a bill. As soon as there is a signature of the recipent underneath, it becomes a receipt and the amount is legally considered to be paid. If there is a second stamp beside the signature or not is of no consequence.
The bill/receipt states #5914 was a rifle in 9.3x74R, perhaps a double rifle, no maker mentioned. How do you get the idea it was a Barella? The Barella guncase, the shotgun #5329, the rifle #5914 and two scopes are listed as seperate items, connected only by being sold by a country gunsmith to the same man on the same day.
The second bill is completely unrelated to the shotgun #5329. It concerns a scope by Kahles, Vienna being mounted, most likely by fitting claw mounts, on an unspecified rifle. This may have been rifle #5914 bought by Capt. Fred Hicks two months earlier or any other rifle. Hicks may have ordered the rifle he bought on 9.1.1946 to be mounted with a new scope and collected the completed work only on 11.18.1946. Perhaps Amrusch had to order the prescribed Kahles scope himself, hence the delay.
IMHO the rounded action boxlock ejector shotgun #5329 already came with some engraving in 1927, but those many gold inlais are very unusual for a 1920s German boxlock. OK, they may be original to the gun, but they also may have been added post-WW2 as well.The world then was full of unemployed German-trained engravers and gunsmithes. Several engravers survived by orders through the Rod-and-Gun Clubs then to enhance war trophies with engraving, inlais and even dedication inscriptions by famous Nazis. The gold inlay under the action bar is in a place that was perhaps left void for the retailer's adress, those on the top lever and on the foreend iron are where the numbers "1 or 2" would appear on a pair of guns. Note the inlay on the foreend iron runs over the borderline of the engraving.
