It depends in which context you want to use the word AI. As a marketing term it is definitely correct to currently do so. But from a scientific standpoint all the terms AI, ML and even neural networks are disputed to be correct, as they are all far from the biological reality. AGI imo is the worst of all because it's just what AI hype men came up with to claim that they have true AI but are working on this even truer AI that is just around the corner if we just spend 5 more gazillions on GPUs. Trust me bro.
Point is, saying that GPT is AI depends on your definition of what constitutes AI.