I now found some more scenes, also some girls in white Adidas shorts (sitting on the balls) and a boy shirtless in 70s style orange shorts. Also a shirtless hippie teen boy in yellow bib overalls and girls in bib overalls (update on my overalls blog, rating ~3-5).
I still don’t know the complete movie, but I assume rather few shorts scenes besides these, if any.
The pics in the main entries are better. Although few scenes, I think I still give rating 7. New tags: white, shirtless.