Still can't find files for PA or NCR/Desert combat armors ;p
Desert Armor and Helmet and NCR Helmet were in reloaded002.zip (as it was the latest update).
cmbt_armor_desert_inv.png (and "_ground" instead of "_inv" for items)
cmbt_helmet_desert_inv.png
ncr_combat_helmet_inv.png
Some may be packed in other art folders (like pahelmetground.png and paground.png were in art/items), so unfortunately you'll have to search them all to get what you want.