I bought them new in 1979. It's my understanding that Barry jones left Charatan in 1978 to join Major Barnes in forming Tilshead, so these must be very close to the beginning. Sadly, there are no hallmarks on the sterling band which would make the dating a cinch. That probably means that they were originally intended for the US market, as the only US requirement is to mark them "Sterling" or Sterling Silver". The rules in many areas of Europe still require the hallmarks.
*edit* - ahh, I missed the "where"... purchased at a Tinder Box in Indiana.