R-Model Questions

Hey there, new to the forum and thought I would post a couple of questions.
I have noticed a unique difference between the later R-Models from the earlier, all 65 of course. For instance I have seen several of the later ones sporting 1966 grills and 66 side stripes and GT350 side names. Is this because they where starting to build out the 66 cars already? Was Ford already suppling Shelby American with 66 K-Codes since they do the change over mid year, or are these poor restorations?

Thanks for any and all answers.