Almost certainly a repro.
If it was done recently here in UK, then most likely an Accumounts bracket given their availability, although there are some eastern european made one floating around as well, but I have no idea how to tell the repros from each other.
The best repro mounts were made by Robert Spielauer but he stopped making his repro's about 3/4 years ago now. He wrote what is probably the definitive book on the WW2 Germansniper scopes and mounts, but again, its now out of print and very hard to find a copy.......although, it is still available in a Kindle electronic format from Amazon if you have a Kindle.