I started to go through the process of purchasing this game using the link that was emailed to me saying I could get it for twenty dollars as a registered stardock user. But I paused because I'm not sure if this "upgrade" offer will allow me to redeem my copy on Steam, and that's something I'd like to know before I purchase. There's not notice before the confirmation screen on the site. So I was hoping I could ask here.

It's a matter of convenience for me. In the future, when I eventually upgrade my motherboard, hard-drive, or whatever, having it registered in my steam library is just more convenient. So, if I purchase it through the upgrade offer, will I recieve a steam key?