Its hard to tell on my monitor but it looks a slight bit different, finish and patina-wise, than the action. As if it may be a later add-on. Even if it is, Holland's could've installed it. Love to see the ledger page for it. I've seen a few flip-up peeps similar to that on W/R, H&H, and Purdy doubles but never a Brit magazine rifle. The G&H and Hoffmans with the rear square bridge inlet for a small peep are cool, too.