One attaching screw is mising but it can be replaced with modern one. German acceptane markings are very clear.
The adaptors are very rare because not many were made and many were scraped after the war because plenty of Russian bayonets were available. Please pay attention that to fit the rifle the stock must be shortened. The item "German WWI period Mosin/Nagant ersatz bayonet adaptor" is in sale since Wednesday, July 05, 2017.
This item is in the category "Collectibles\Militaria\WW I (1914-18)\Original Period Items\Germany\Edged Weapons". The seller is "buldozjor" and is located in Adazhi, Latvia. This item can be shipped worldwide.