In order to not repeat it over and over i am going to refer to the more advanced society as mas and the less advanced society as las. Also i am going to use human rights as a substitute to mean the established rights of whatever species each society may be.

Unfortunately, the mas does get the privilige of defining the laws. At least they do assuming the mas wins the war/extermination/enslavement that would most likely happen once they started trying to force their version of basic human rights onto the las. There have been examples of this throughout history on earth.

However, the mas may decide to try and coexist with the las and respect their version of human rights. After all, if the las has developed their own version of basic human rights and is able to communicate them to the mas it would demonstrate a certain level of consciousness to the mas.

My opinion is it would depend on how much more advanced one society is from the other. For example, animals have not communicated their own version of human rights to us, they do not display a very high level of consciousness, and they arent nearly result humans (as a whole at least) do not respect their way of life. Yet we do give some rights to certain species that show higher levels of conciousness. If elephants suddenly were able to communicate a set of rights they wanted to be allowed to follow there would most assuredly be an enourmous amount of people in favour of it.

Either way it gets very muddled. Even on earth many of us do not follow our own version of human rights.