This is plausible. One of the top chess engines in the world (Leela) is just a neural network trained on billions of chess games. So it makes sense that an LLM

This is plausible. One of the top chess engines in the world (Leela) is just a neural network trained on billions of chess games. So it makes sense that an LLM would also be able to acquire some skill by simply having a large volume of chess games in its training data. OpenAI probably just eventually decided it wasn't useful to keep pursuing chess skill.