Did James Doohan visibly age the most between the end of TOS in 1969 and The Motion Picture in 1979?
I know that he along with DeForest Kelley were the oldest among the core 7 cast members. I don't simply want to chalk it up to merely, Doohan suddenly sporting a mustache as Scotty when he was clean shaven during the original series.
https://boards.straightdope.com/t/actors-actresses-whose-looks-changed-drastically/922813/28
For the sake of reference, here's images from the final episode of Star Trek: TOS, "Turnabout Intruder":
https://www.google.com/search?q=Star+Trek+Turnabout+Intruder&tbm=isch&ved=2ahUKEwjeoZq74ODtAhVLHKwKHR82Am8Q2-cCegQIABAA&oq=Star+Trek+Turnabout+Intruder&gs_lcp=CgNpbWcQAzICCAAyBAgAEBgyBAgAEBgyBAgAEBhQ_0JY2Exg3FdoAHAAeACAAZcBiAGWApIBAzAuMpgBAKABAaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=TXbhX57HGMu4sAWf7Ij4Bg&bih=732&biw=1600
And then from The Motion Picture ten years later:
https://www.google.com/search?q=Star+Trek%3A+The+Motion+Picture&tbm=isch&ved=2ahUKEwiLn6HmsbbsAhVIja0KHQl2Dn4Q2-cCegQIABAA&oq=Star+Trek%3A+The+Motion+Picture&gs_lcp=CgNpbWcQAzICCAAyAggAMgIIADICCAAyAggAMgIIADICCAAyAggAMgIIADICCAA6BAgjECc6BQgAELEDUK77AlibnwNgoqEDaAVwAHgAgAHSAYgBmBuSAQYwLjI3LjGYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=WySIX8uFK8iatgWJ7LnwBw&bih=732&biw=1600