S&W ammunition was made by Fiochi, and was offered in several calibers that S&W didn't make guns for. The early headstamps were S&W-F, and the later ones were plain S&W.
This was done when S&W was owned by Bangor-Punta and they had all kinds of different ideas on how to promote their business. Bangor-Punta also owned Taurus at the time, which is why so many of the Taurus handguns closely resembled the S&W handguns.
Only full boxes of odd calibers of the old S&W ammunition have any collector value.
Hope this helps.
Fred