Mr Light wrote:
I was operating under the assumption that David was the first of his kind, the prototype, and no others had been made yet.
In the promotional videos David is the eighth generation of his kind going back to at least the early 2020s, and as mentioned above there were others that looked like him. His was the most highly advanced in terms of understanding and mimicking human emotion, while not being able to feel emotions himself; or so he says, though the film seems to imply otherwise. Either that or his mimicry of contempt and wonder is so precise as to be indistinguishable from human emotion, in which case the difference between them being real emotions or not is largely a moot point.