Any pics of a bare 1975 duster Firewall ?

I have a 1975 Duster, it came with heat/air. The cowl is different from a 1969 Barracuda. The air doesn't enter through the cowl, and down into that box with the door at the bottom/front. The whole cowl that is welded to the firewall seems revised to me, from the earlier A body cars. Does anybody have photos from a resto of a bare firewall, freshly painted is fine too ? I want to weld on the engine side of the wall, but I want to be sure I can do this safely. Thank you.