Hey, well you found treasure there for sure, be it old or new. The likely hood of it being old, to me seems slim. As it looks very "new" style. It looks to me like gold plating, but its hard to tell with photo's at times. but it seems to "sharp".
I do not know if they have modern reproductions or not,
Sadly, these are hugely reproduced. Especially with the gem intaglio's and real gold. They are produced as fakes, even as old as roman times. They were big sellers for counterfeiters years ago. Still float around, sadly in many collections etc, as real. Even if as just a gold repro, was worth the jewellery value, and if sold as "real deal" could fetch larger sums, due to them being quite collectible. "newer repro" were many times plating on cheap alloys. which you can tell. these were not sold as fakes, just repro.
Either way, I love seals. they are really neat.