Noticed that during 1966 production of the Mustang (and in turn Shelby) at the San Jose/Milpitas plant that the top front splash shield retaining screws had a change in finish and in turn suggests a change in what parts were attached to the unibody during the paint process. The screw I'm describing is visible from the engine compartment and attaches the rear splash shield in the front wheel well to a transition panel between the rear inner fender panel and the cowl of the car. This change was pointed out in the article in the Library covering how to redo the undercarriage of the 66 San Jose Mustangs.
In 1965 and starting out 1966 production there we find the screw unpainted suggesting that it was added after painting was completed since it does not have primer, exterior paint or even overspray from the engine compartment paint application. On later cars we find the screws on unrestored originals to be painted body color suggesting that the splash shields were attached before the exterior body and trunk were painted.
Other examples are shown in some of the threads in the Unrestored Picture thread section of the site.
Transition appears to have taken place around 6R1725xx-6R177xxx of course the cars were not built in sequential order so we can't come up with an exact change over date only a period. Do have one orphan example that is out of this range but since its a single I'm going to leave it out of the count unless we find others built close to it.
