Yes, that is correct, CSS Sculptor requires DW CS3 and above.
Other extensions with this requirement are:
CSS Form builder
Digital File Pro
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.