woodsltc

I'm not either of those guys, but the L stamped on the cylinder indicates the threads on the extractor rod were left handed. That is the change that the dash 1 indicates.
On the HP, the dash 2 change came along before very many were made with the LH extractor rod and the change was rolled into the dash 2, along with its redesigned cylinder stop. Hence the rarity of the Model 28-1.
I hope this helps.
Jack

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Jack
SWCA #2475, SWHF #318