I personally believe that all living organic beings have souls and can enter heaven. I also believe that sentience is a somewhat relative concept formed by an an egoistic species that likes to see the other species of animal life on this planet as inferior. So the soul is and has been ever-present, and there was never a time that anything "gained" a soul, except at its instantiation. Which makes it hard to think of it as possible for any piece of hardware to have a soul, since that would pretty much require steel and silicon to have latent souls or something.I see you and raise you this: the emergence of true AI disproves the existence of souls in anyone.
Occam's razor. If a sentience can be created through--or is emergent from--the technologies of man, then souls become a superfluous concept and can be disregarded entirely. If sentient machines are created without them, and are just as intelligent, concious and sentient as we are, then they clearly don't need souls to be alive. By extension then, neither do we, and we can move past superstitious frivolities and into more practical and realistic (and therefore productive) concepts of reality.
I don't believe in souls, and I think artificial sentience is a matter of time.
/as