Drew, the letters I've seen from the 50's usually state something like "with the information you've provided it's a model X". I may be wrong on that, but I think there was a lot less info written down. And as to RS's versus R's - just going off of what I've seen and the same logic as you state. Why pay more for a tang sight when the scopes were becoming so popular? There's a LOT of R's out there that have never had a scope mounted, but very few that are set up like an RS - and even fewer that look like they were set up that way originally.

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