Possibly, the Chinese in Zhou times may have known about Japan. But I can't say for certain that they were aware.

The first mention of Japan (Wa) corroborated by an archaeological link between Japan (Wa) and China is found in the Later Han dynasty. There's a tiny mention in its history and there's a gold seal sent by Emperor Guangwu of the Later Han dynasty that was unearthed in Japan.

The first detailed description of Japan (Wa) in Chinese records is in the History of the Wei of the 3 Kingdoms period.

Any mention of Japan (Wa) before the Han dynasty may be confusing the Japanese with other "Eastern Barbarians" and there's no way for us to know at this point.