The "student radical" would be of university, not of high-school age, and the style would not be much seen before the "cultural revolution" of the second half of the 1960s. Secondary schools in continental Europe did not then, and do not now, have official school uniforms, but most in Britain and Ireland did and many do still.In Europe I understand that dungarees or work pants, turtleneck sweater and leather jacket was the uniform of the student radical, copied from the working man's everyday clothes. This look would not have passed the eagle eye of an American high school teacher.