I now have both movies on my overalls blog.
Both showing boys in jeans overalls and regular jeans. However the 1949 movie (pictured) has a 9 yo boy in simple overalls (or in fact 2 boys), rating 4.
The 1973 TV movie starring 13 or 14 yo Clint Howard (and Henry Fonda) is much better but very rare (rating 6). That also has wet overalls and sitting scenes.
They are rather ranch movies (novel by John Steinbeck), but the setting is much earlier than thought, so also real western movies as well.
If someone knows the 1973 version or can provide better pics please comment.
For more infos and pics see my other blog.