Gargoyle Minority Protection Act
At some point between 2004 and 2188 in large part due to Goliath's sacrifice and the efforts of gargoyles and their allies to improve their reputation among humans, the United Nations approved the Gargoyle Minority Protection Act (GMPA).  It granted the gargoyles basic rights as a protected minority, treating the scattered clans around the world as a single nation-state (referred to simply as the Gargoyle Nation), and made it a crime to hunt gargoyles (unfortunately, it did not completely remove human prejudice against gargoyles and groups such as the Quarrymen continued to exist. The gargoyles were willing to accept what they could, however).
Though the GMPA could have been passed at any point between 2004 (the last year Goliath is known to be alive) and 2188 (the earliest year known that the Gargoyle Nation was in existence), Greg Weisman has stated that "...I'm fairly certain that 2008 is way too early for the GMPA to have passed." 
Real World Legality
One indicator of how far in the future it might be before the GMPA can come into force as it is described is that the United Nations presently lacks the authority to pass any Acts of law which would be binding on member states without action by each member state's sovereign legislative or equivalent body.
Current Status of International Law
International law is considered as a matter of custom, that is to say that there is no set international code of law that dictates the actions of governments or their citizens. Although nation states may ratify treaties or provide material support to organs of the United Nations in order to achieve common goals, no nation state is governed by or subject to a higher law in the same way that a citizen of a nation state is subject to the laws of his or her country. A nation state's adherence to "international law" therefore exists opinio juris, or when it is the sense of that nation that it is expected by a majority of other nation states to behave in a certain manner, not that it is obligated to, even if it might be in the minority of international opinion.
The legally binding nature of Security Council Resolutions, for example, is not that they become the force of law on the citizens of member states, but rather on the governments of member states by what is, in essence, the contractual agreement member states signed in the form of the United Nations Charter. Each member state is left to execute the will of the United Nations in its own manner, most often by authorizing the release funds or material support to support the operation of the United Nations in achieving the goals of a passed Resolution. But when a nation violates a Security Council Resolution, other nations are not immediately compelled to punish the offending nation; indeed, it requires another Security Council Resolution to authorize sanctions or military action against the offending nation, if such a method is not outlined in the original resolution, which once again is up to the nation states to support on their own terms.
The International Criminal Court, the world's only international trial court, also lacks the jurisdiction to prosecute crimes other than genocide, crimes against humanity, war crimes, and the crime of aggression. It does not even have jurisdiction over crimes of aggression at present. And unlike the International Court of Justice, which serves in an advisory capacity, member states of the United Nations are not automatically subject to the ICC's jurisdiction. Member states can even accept or reject the ICJ's advisory opinions on a case-by-case basis. The United States of America, for example, has not signed onto the ICC, making its citizens immune from prosecution, and only regards the force of the ICJ's opinions on a case-by-case basis.
Furthermore, with regards to this peculiar topic, the protection of species on an international level is conducted by the World Conservation Union, which is not a body of the United Nations, and which works with nation states and NGOs to protect species. But despite the IUCN's coordination efforts, the legal penalties for persons who hunt protected species varies from one nation state to another, as does the level of recognition each nation state gives to protected species.
And even if the United Nations and the international community recognizes the existence of a gargoyle nation state, that nation state would have to sign on to the United Nations Charter in order to join the General Assembly and be afforded a measure of protection under the United Nations Charter. It is unclear what methods the Gargoyle Nation would use in order to become a member of the United Nations that is satisfactory to at least a majority of the confederate clans.