If those photos with painted clouds, etc. were presented as depicting reality, I think it's proper to call that dishonest, otherwise no. I guess the cructial difference is whether the image is meant to document a situtation, or to present the photographer's interpretation.
It was also common then, and now to retouch wrinkles and blemishes in portraits, for the most part, I don't think anyone calls that dishonest, though it's certainly over-done sometimes.
Certainly, all work, documentary or not is colored by the photographer's, writers's, artist's interpretation though, so the difference can be a very fine line.