Yea, it was announced in a steam post.
"Similar to Insurgency, we plan to support Insurgency: Sandstorm with free content updates post-release. We will continually expand the game with new weapons, upgrades, maps, and other content. Modding support is something we are committed to providing. We want to work with our modding community to give them the tools they need to create exciting new content beyond what the official experience offers. This includes Steam Workshop integration, custom map tools, game rule adjustments (similar to Insurgency’s theater system), and things of that nature."