yes, as far as I know it's only been produced once. The navy luxe lambskin does have signature hardware too.
I do think there was a special order navy luxe mac produced more recently, but only the mac has been done as a special order bag.
A lot of people have said Stone is lambskin, but it's not that easy to tell really. RM doesn't say what leather it is on the tags and there's some calfskins that can be as soft as lamb.
But most RM bags are calfskin... she's said before in interviews that she prefers cow leather because she feels it ages better.