Yes, but those "models" are not equal. Best I can tell from observation, ChatGPT seems built around two components: the GPT model that's got everyone so excited, and a bolted-on hamfisted "censor" component that restricts the user-bot interactions in order to minimize the amount of bad press OpenAI will get when journalists and Internet randos inadvertently attempt to generate dramas.

The distinction is important because the censor component is just an annoyance nobody cares about - all the interest is in exploring the capabilities of the GPT model.