So looked through my collection and samples, when compared to other plants, are limited do to the condition of most unrestored cars and the lack of people taking pictures of those area. Most possibly likely due to the condition and amount of rust
I would suggest that you read the article in the Library on Detailing the 69 Dearborn Undercarriage if you have not already done that. The information, as far as color application, overspray from body paint and pinch weld black out will be very similar to 68 at the same plant. IMHO a good place to start
Don't have Marti reports for all my samples so will use the VIN's to at least get us in the neighborhood. Of course we can not be certain how you car was specifically painted originally but other cars built around the same time appear to be shot, from the firewall rearward with a batch color. Mixture of m epoxy primer base with left over paint from the prior day or shift. As mentioned in multiple threads this typically, prior to 1970, resulted in a gray final look (medium to dark - most often dark) with a blue or greenish tint to an almost black look in some examples.
Below is an example from a car with the partial VIN of 8F163xxx showing a medium gray bluish color in areas where the owner/builder had cleaned away the oversprays and road grime. You can still see some of the exterior color (yellow) on one of the floor ribs
While we are here here is an original picture showing a car built about a month before yours and the amount of body color overspray (very strong) and a close applications with allot of runs from the black out paint application along the rocker panel
As far as front wheel wells much of the painted surfaces will be covered by the sound deadener application applied right near the end of the build with fenders and just about everything installed. Just the opposite from the rear wheel wells where the sound deadener was applied even before the body was painted
When painters at Dearborn painted the exterior they often applied the body color up to, approximately, the rear edge of the shock tower opening. In some cases a little less and on others all the way to the radiator support. When the next painter applied the black to the engine compartment and the face of the radiator support and the front cross member they often/normally continued the application of black paint onto the forward inner fender panels on the wheel well side reward maybe a foot, to the shock tower inset or to where the hood hinges were going to be attached. The rear edge was not masked nor was it straight and the painter stretched or leaned likely during the process standing lever with the body
Here are some examples showing some of the variations I attempted to describe above
Body color to the shock tower insert
8F136xxx example. With a dark exterior color the contrasts are not as great as in other pictures and examples
A ton of body color - not very typical IME but wanted to share since it did happen
Hope this helps