Very interesting.I've been going through some old trade papers (american cutlerer from the 20's) and I think I know what you have, but you don't have all of it. Torrey kept on making straights well into the DE period. The basically made a open comb guard that slid onto the SR.
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I have a razor with similar groves though that appears to be a lot older than the 20ies. But then again, it is hard to tell.
Also, in the poster, the guard appears to be flush with the top of the tang, which does not seem possible for the Torrey with blood groves as the top of the blade is flat.