You obviously can't carbon date the gold itself (because there's no carbon). But okay, sure, you can date the soil around the find. But how could that disprove a claim that archaeologists placed the gold figurines in the soil? You'd need a perfectly recorded chain of history of the dig.
"You'd need a perfectly recorded chain of history of the dig."
Yeah, but how do you perfectly proof in the first place, that it is really you asking those questions and not a implanted computerchip in your brain, or that you ain't living in a matrix? (Or me)
The philosophical answer is, you cannot.
But you can indeed donate to research, that they can hire more people, to check integrity in various ways, because generally, they are very low on funds. So yes, making fraud is an easy way to get reputation - but exposing fraud is as well, so personally I do trust them in this case until proofen otherwise. Because I see no indication of fraud here, do you?
Proper archeology carefully excavates a site and observes and documents the soil of the dig as they go through the various layers. You can tell from analyzing the soil layers if they have been recently disturbed.