It's legit - the original Silhouette Specials had that Wilkinson 6-screw bridge (actually if you look very closely it's more like 2 posts and 4 screws) plus those thumbscrew top Grover tuners (which Tom Anderson also used for a while in the 1990s). Check out how the holes in the back plate match up perfectly with the staggered holes in the Wilkinson trem plate - as always nice design work from EBMM.
I've always liked these early ones in that green color - the one I played in person circa 1995/96 was a bit darker looking than that the one in the auction - it was closer to metallic "British racing green" but the auction guitar could look lighter from the flash.