yes, I think so...the separate firing pins are part of the improved lock system, at least for the '94...you'll have to give me some time to say for the 1900...But who can tell exactly when each improvement was incorporated...I have many more questions than answers...were all improved lock '94's four bite?... are all improved 1900's two bite? Do the two bite, three bite, and four bite lock-ups coincide with other keystone changes? All of these variations should be considered when dating a Rem SxS...I don't have Semmer's book, are these topics covered? Was this info discussed here, in the past, and I missed it?
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One thing is for sure, Remington SxSs are one of the most under valued doubles on the market...