Yes, solid nacre (tissue nucleated) freshwater pearls have been farmed (cultured) in China for decades! I have some from 1980 but they date back before that. As time went on the Chinese figured out how to produce rounder shapes.
These days you can get much better Chinese cultured freshwater pearls-- rounder and larger, and better colors. That is why I am not urging you to buy them! You really can do better. However, if you prefer those eggy shaped pearls, you would not be overpaying if you paid $10-20/strand for them.