Probably younger than 6 months. Not pure barred Plymouth rock either. They don't have solid colored feathers. That being the case, you cannot sex based on barring color. Barred cross males can have the dark barring typical of a female. Black sex link males (gorgeous birds btw) are dark barred and often confused for female barred birds... until the comb comes in.
The one sold as a cockerel is looking like a male. Not sure on the other.
The one sold as a cockerel is looking like a male. Not sure on the other.