They might merely mean Gendarme 20, which is an edp of the original edt. I've smelled it, and it's not bad, just denser with the white tallow soap note that's in the edt. Not a bad scent at all if you like the edt, Joe, and I'd say go for it. My tastes in the Gendarme family have gone toward V and Carierre, the one marketed for women, since it has a hint more floral sides to it.
I expect that Barney's just getting Gendarme 20 in, which has been at Nordstrom and probably elsewhere for two years or so. I don't think there's another Gendarme edp, but if I'm wrong I hope another member will correct me.
Hope you like it when it comes around too.