The ring plate is attached to the ring band and the plate has a curved form. And it is technically much harder to make such enameled ring plates or at least to finish them correctly. Odal, are these the reasons You belive it is not an original one?
If this ring is a modern fake it is a very well made one. It is easy to make a casted ring, it is more harder to make the correct dies and to produce a die struck ring. But the hardest is to make die strucked enameled rings. I quess it is just not worth of money.
Rather much work, but no Problem for a professional.
Of course such work is still done today....ring prices rise and there is to earn
a lot of Money.
Here for example a comparison between a rather rare period Kirkenes ring and
a die for faking such rings. Notice the differences of the plate