Whitey has the (maybe) somewhat rarer Field's Patent sidelever Martini action, and it too had the smaller additional/safety side lever that locks the main sidelever in place. This additional small lock lever is to prevent the main sidelever from inadvertently being moved while stalking, thus accidentally opening the action. I've seen several Field's sidelever falling blocks but only one Field's Martini, thus my statement that the Martini action may be rarer than the falling block one. Unfortunately Whiteys' smaller lock lever was removed when Bubba renovated his action, but the evidence is still plainly visible. Whitey's sidelever and his other action furniture & architecture are identical to the H&H shown with the single exception of the upper tang extension and safety. It's my assumption, based on this furniture shape similarity, that the basic actions were produced at a single location and then sold to the various assemblers such as H&H, Westley Richards, etc., who then added their own unique touches when completing the rifles.
Regards, Joe