They did it for 2 and 3, however it looks like they didn't for 4 and 5.
GPT-2: https://slate.com/technology/2019/02/openai-gpt2-text-genera...
GPT-3: https://www.itpro.com/technology/artificial-intelligence-ai/...
GPT-4 was announced in March 2023 and wasn't made available to all developers until July 2023.