I don't know. It would seem pretty pointless to pay someone to use their likeness when creating one of these things. Using yourself as a model is probably the most cost effective and time efficient way to go about it.
Artists are often told to keep a self portrait in their portfolios. It shows a prospective client one's abilities when the imitation of life can easily be compared to the subject. I suppose if we presume for a moment at least that these scientists are not just complete egotists, there is a valid and logical reason for copying yourself. You can show funders, prospective funders, your boss, and whoever just how life like your android is (or maybe isn't). Nerd hat off.
I wouldn't say is narcissistic at all, its what makes most sense. As others have pointed out, the model for the face needs to be available at beck and call during construction and then during testing and they can avoid having to pay someone to use their likeness.
Me, I'd use Surya Bonaly or Linda Park. Or maybe Fay Wray or Myrna Loy. Depends on which era my head was in at the moment.
How self-centered was that? Not at all. People had written autobiographies or painted self portraits before. If he had modeled it after a beautiful woman, people may have questions about his "after hours" work.