Steve McQueen salute

There's an entry from a group at FB explaining this picture:

"Steve McQueen finger salute in Le Mans.

This gesture is English in origin. Hundreds of years ago when the French and English were at war, the French would cut off the fingers of the English bowmen when captured so they couldn’t use their bows anymore. The English bowmen would therefore taunt the French across enemy lines by using this particular gesture."

There's no mention of the source where they took this info, anyway makes you want to watch that movie to get the full context.