The gun in question is certainly legit. I'm not sure I understand what you mean by the term 2nd style rib, as the rib matting appears to be identical to the early Smith guns I've seen; but the stepped lock plates are a standard feature of the early First Variation Grade A-2 gun, and seems to be the feature that makes these early A-2s so desirable amongst collectors (and the fact that examples are so hard to find). This gun has seen lots of use judging by the position of the opening lever and the fact that the dogs head forearm insert is worn smooth; the forearm also has a crack that needs addressing. I can't remember if Jim's grades recap includes the
A-2 manual extractor guns, but Brophy's recap recorded only A-2 guns with auto ejectors. I've seen one other A-2 extractor gun that ultimately wound up with John Houchins and which I believe is pictured in his book LC Smith, the Legend Lives. That gun is engraved very similar to this example. The pics below are of an ungraded, but certainly very early A-2 quality gun in the 24XXX serial number range; and the engraving on this gun is outstanding.
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