If the plate had been soldered on separately, it may have stood a chance, but this one is one solid piece and is a very commonly faked pattern-one of many Norge 1940 types. Not authentic.
"Much that once was, is lost. For none now live who remember it."
The pattern is real.
A norway made souvenir ring. Most worn by german solders.
But this one is for sure a modern made fake. As William told, one point of originals is that they are 2 piece made.