WHAT DOES DAN WESSON SPECIALIST MEAN?

Bushnell made loads of mounts again in the 1970's and early eighties. This just one also replaces the rear sight and demands drilling/tapping the highest strap. Good aluminum and really light-weight.Furthermore, it has a two line roll marked shroud likewise. I am aware they transitioned to 1 line roll mark barrels, so perhaps it is a transition gun