Bought this at a recent small auction for €100. Someone else mentioned it's an "official museum replica" rather than genuine.
Since my expertise is mostly in Romans, I must admit I'm sort of out of my depth with this one. It's not ferromagnetic and the weight checks out at 3.76g, but I am concerned about some of the surface marks.
I hope someone with some more knowledge in these can weigh in and help verify (or not) the authenticity.
There's not a single example of the AR unit on acsearch.info - and that has auction records going back decades. Which either means they're impossibly rare, or I am looking for the wrong thing, or it's indeed some sort of copy made to look very very genuine.
I mean, it could be either of those three. Or maybe the light is off and it's actually gold, but I am sure you'd notice the weight difference.
It's definitely not gold, alas.
This weekend there's a chance that the person who told me it's a fake will be present, so I'll take it back to him and ask for elaboration. Thanks for the insights so far, has definitely helped!
Afaik these were Electrum, and some of them look very light indeed. It should weigh something like 5g if it's and EL stater, which is of course well over what yours weighs.