Almost all AI Text on Perchance uses the same model. Some are calling other through external API. But based on both that you've linked, yes, they are using the same LLM. From what we know from the plugin page ai-text-plugin it is a LLaMa based model, but the specific model is unknown.
Nobody knows the exact LLaMa model? Its for sure open source and should not be a secret?
From my actual tests with the same prompt given to different models i would also say its a LLaMa based model. But which exactly? Because it works for my need perfectly.