If there were a difference which affected movement or combat (ranged combat, in this case), the scenario would mention it.
I'm not sure I have as much confidence about this as you. Some scenarios do specify line of sight in the special rules (e.g. The Heart of Darkness), but others with level changes do not (e.g. The Wrath of Anu). The artwork on the map is used a lot for LOS bits, so possibly the same for elevation. I specifically asked about elevation on this map on the Monolith website under this scenario, but my comment is awaiting moderation and is currently unanswered.