Quite a number of original street model GT350 Shelbys have been modified, converted. upgraded (select one) to R models, even some born as 1966 cars,but we seem to like them as long as they are not misrepresented as original R models, I guess.
I am not sure if this equates of using original K code Mustangs to make licensed continuations in a Shelby owned facility by former Shelby employees.
Just stirring the pot a little without negative comments about this. Personally, for the price I would rather have the correct original Shelby and use a 66 Mustang for the modified ones that contain modern upgraded parts. This process has been done for decades and the results, which are usually very appealing, are usually termed tributes or clones or some other confusing label.