I think that any sentient extra-terrestrial lifeforms should be allowed rights equal to our own, if they so desire them. However, one thing that should be taken into consideration is what exactly counts as sentience. One species may have an entirely different idea of sentience, or their mental capacities may be beyond human comprehension. Either way, it really comes down to if they desire to be considered equals.
I also noticed many people have decided that hostility would prevent them from receiving rights. The one thing I find to be really odd about this is the consideration of an entire sentient race being hostile to us humans.
As a final note, I would like to add that we're all aliens to aliens.