Players will be running into plenty of things they want to shoot in the New Vegas wastes. The second Fallout: New Vegas developer diary shows off plenty of ways to kill them.
You can keep your steampunk; post-apocalyptic weapons are where it's at. The developers at Obsidian Entertainment channelled the 50's sci-fi mindset in New Vegas, coming up with designs that combine the creativity of that age with the technology of the future. I'll take colorful streamlined laser guns over brass pistols with gears glued onto them any day.