In the process of restoring my 69 Mach 1 I have noticed that some 69 Mustangs do not have the proper square hole reliefs in the apron rails for the "fender to hood" bumpers. These are the four bumpers that fit through a rectangle holes on the top of the fenders. Look at the enclosed pics.
Of course your comparing pictures from unknow sources and back grounds so you have no idea if what your comparing are originals or other repaired/replaced ones. Also there are two different panels used on the drivers side during the production year. So when comparing/asking how it relates to your car it would be helpful to know what plant and wne your car was built so we can compare "apples to apples"
Not all 69's have a relief in the aprons for the bumpers. Is this normal on some cars?
Think your statement is likely based on what your finding/seeing on the internet. Not sure why you included a reproduction panel in your post since you can assume that it at a minimum is designed only to fill a void