Hi Raimey, these are not order forms, but bills/receipts for a lot of apparently unrelated second-hand items, both dated 1946, short time post-WW2, while the gun is clearly much earlier, though overrestored recently. The bills read:
1.) September 1, 1946
1 complete guncase
1 shotgun number 5329, 12 bore
1 rifle cal. 9.3x74 number 5914, engraved
2 scopes
all in all Schilling 8000.-

2.)November 18, 1946
1 scope by Kahles S 240.-
mounting S 180.-
total S 420.-
The stamps and signatures say that the amounts have been paid.

So the shotgun is only mentioned in receipt nr.1, only with the serial number. Remember, in 1946 neither Germans nor Austrians were allowed to own any guns. Allied officers could then buy guns for a song or some packs of cigarettes. At that time about 20 Austrian Schilling were one US$.