[camaromb]

Paul,
If you look at your original firewall where the 2 is written you won't see any blue overspray from where the side cowl was painted blue. The overspray is later covered with the firewall black. The firewall black is painted after body color, as is the dash top and rear inner window black areas. There must have been some templates that the factory used to prevent overspray when the black was applied.
The body color was sprayed over the top of the firewall by hand, catching the trim tag highlights and going over the edge depending on the sprayer!
The firewall black frequently ends before the top of the firewall on original cars resulting in a 2-3" band that slowly rusts. I have seen bare tags with no paint and half painted tags from the factory. Nothing perfect and certainly no crisp body color seam at the firewall top.
The hidden areas of your firewall that were under the fender will give you the best indication of the original firewall black. Good luck with the resto!
Mark