The PC being an android would make zero sense. First off, that would mean the pre-war period is some sort of dream. Why would you, as an android creator, want to program into your android an emotional attachment to other people and the determination to get out there in the world to find them? You want your android to believe it is your property, not a man in charge of his own fate.
Second, Harkness is said to be the most advanced android created by Zimmer yet. The PC would have to be on par with Harkness and such models must be very rare. Making it all the more unlikely that you would have your android believe it's human.
Third, the vault. The vault is not the Institute. To have this android manufactured in a vault makes no sense when it could have been created in the tech haven that is the Institute.
I simply don't believe Fallout 4 will be The Great Android Game Where Everyone Is An Android And You Are Also An Android 4.