Mtn, that looks like the classic Stanley storm window adjuster set, which is still being sold:

Killian hardware is a nice place to shop online for those and other authentic window restoration needs. You can easily patinate the new metal with store-bought darkening solution.

And there's always eBay, which would be my definite first place to look if I were looking for used sets:

windows, sashes, and locks category

Robinson's is where I got all of my old hardware. He was wonderful stuff and good customer service. He also will find things for you if he doesn't have it. c

Here is a link that might be useful: Robinson's