Adding AC to Duster

There is/was a member here who ships a firewall section as loaner template. I used it clamped over my non a/c firewall ( engine and everything else out of course ) to mark where every difference is. I measured and marked several details on my firewall and his template. Like outward offset 3/4 inch here, hole diameters, etc...
Please note, this template is from a 67-9 a-body. I don't think there is any difference before every dang thang changed for the 73 model but I've been wrong before.