Casting observations
Judging from the full assembly scene at around 06:30 in the movie, I'd say there were around 110-120 boys. That actual camp alternated boys and girls sessions. It was not coed.
The kids did not look average. Certainly not for today, there were no real chubbies. But even in 1987, they must have been screened for Hollywood type good looks. Judge for yourself.
There was only one black kid, that is among the extras. Moustafa makes it two.
There were only three or four females in the movie. The males would include those 120+ campers, the camp crew and the mining company people, (workers + execs = about 22). Maybe a total of 150 males to 4 females.
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The story is king.