Ya the auto updater on first installing steam version pops up. Or with DLC's as well. So long as you hit save and play it does everything fine. Can easily install mods and DLC's from other retailers as well.
Steel Armor: Blaze O War (SABOW)---
ISABOW mod. Check Graviteam forum. New AI vehicle M113a1 with recoiless and M106a1 self propelled mortar carrier. Much of other little stuff too.
Requires AUG SABOW patch from Graviteam. Enjoy