Agreed, but strictly speaking the model would probably still be based on a general model such as Stable Diffusion, then "fine-tuned" to render only interior designs. For example the NovelAI anime image generator was based on SD then fine tuned on anime art, and it works incredibly well - it can generate anime art of basically anything you ask, because the model has the wide knowledge of the Stable Diffusion model but is fine tuned to the anime art style.