"I think they used to do children's sizes in Levi red tab because my younger brother had a pair when he was just a kid. We had paper rounds and Saturday jobs to pay for our gear."

Yes they certainly did - I knew a lad who was so small and thin at 14/15 he had to wear the boys' size, though I think they had maybe a white tag, or the patch was different? I only ever met him once though, and that was nearly 60 years ago, so it's difficult to be certain!