do I need to find an old passport from over 14 years ago?

I was born in China and moved to the US in 1987. I became a citizen in the early 1990s and went back to visit china in early 2001. I have since married and changed my name. Now over 14 years later, I am planning a trip to China as part of a tour and the agent indicates I need to find my old passport with the Chinese visa. I don't think I even have this -- or if it was returned to me when I applied for a new passport over 10 years ago. I have since renewed my passport again so the old passport is multiple passports ago. Is my old passport still needed? What if I don't have it?