I guess the first place to start might be the term "black out" since the are your referring to (the sheet metal sides that attach to the fender and to the face of the radiator support were typically the dark argent/charcoal color.
Help me recall the details of this particular car if you would, to be sure that I remember it correctly. Wasn't this car tapped on the drivers side front fender?? IF I remember correctly they didn't black out the turn indicator pocket and left the upper plate should in your picture on the drivers side body color also. If the cars front end was altered could what we see now possibly be black rattle car be someone later effort to clean up the front end? Car #218 didn't have any black on those surfaces - closest original cars I've owned close to your cars VIN
For others we're discussing a very very early 69 351 (#21) that I think was built in October.
Just asking of course and looking for a solid starting place for discussion
I know the other two (Ed and Bob) aren't back from Monterey as of yet - sure they will join in the next day or so.
A few examples from later original paint car to help the discussion
A couple of pictures of the cars being assembled
Appears to be that the workers are masking off the headlight and grill opening area so that the grey can be applied to the front end before it was installed
Cropped from a larger original picture
Another of the completed front end - notice that that area your looking at on your car does not appear to be bare steel nor unpainted light pick fiberglass/plastic