Yes, they were quite common on exposed hammer guns, but apparently they were also sometimes added to hammerless guns as well. An H&H Royal 450/400 currently listed for sale in NZ is described as having such a safety. "It was Started in 1897 and finished in 1898. It is a Holland Royal No.2 Which is the same as its more expensive No.1 although with only border and minimal engraving. The upper tang extends onto the comb and the rifle is fitted with a "Stalking Safety" as well as the traditional safety with SAFE in gold." See attached photo. I have a Royal in 240 flanged that was built in 1907 in 375 (pre magnum version) and later rebarrelled in 240 in 1949. It shows a similar feature? See attached photo: Curiously, I have all available shop records on the rifle, both the original build sheets and the subsequent rebarrelling order. No mention is made of such a feature.
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