Mark, I just took the front end apart on my other Fremont-built '66 GS.
This car was built in Jan '66. I'm seeing some differences from the March '66 Fremont built car. The March car didn't have any traces of paint on the spindles or backing plates, but the January car has a nice layer of black paint on them.
Backing plates on the March car did not look plated at all...I did find shiny bare metal under bolt heads and gasket surfaces....no plating.
It's possible there are variations at the same assembly plant.
Also, My Baltimore-built 65 and 66's have floor-pan undercoating, but the Fremont '66's have none....