The Making of Star Wars …as told by C-3PO and R2-D2:
https://www.youtube.com/watch?v=FSuDjjlIPak&list=PLYn2a0e2FVIKni_wHXR5CJYBnnnYH7mIB&index=2&t - from the Sanchez del Campo YouTube channel (49 mins long).

Originally aired on ABC September 16, 1977.

The blurb:
“This TV special, the first ever Star Wars documentary, was hosted by C-3PO and R2-D2 and narrated by William Conrad, with appearances by George Lucas, Mark Hamill, Carrie Fisher and Harrison Ford.”

I’ve always found this one to be really charming. It’s kind of silly and not as “in-depth” as other SW documentaries, but considering it was made primarily for children it managed to cover a lot of ground.