The short answer is yes, so Cameron is right and Gove wrong? Well no. The true answer is they are both right if you express it all correctly which neither of them has. They have both left out the tricky bits which dent their cause.
The deal is a legally binding international agreement with the force of international law. It can only be challenged if an injured party can show to the European Court of Justice that some aspect of it breaches the terms of an existing treaty. This is very unlikely but, because some of the issues are contentious and agreed to with reluctance to keep Britain in the EU, it is possible. The European Court sits above our Supreme Court and the UK parliament ceded sovereignty to it by the Treaty of Accession in 1972.
So in the normal course of business it is a done deal but as a matter of law whether it conforms with previous treaties in all respects is not for Britain, its politicians, or its courts to say. The EU Court has the last word. That is the whole idea of it.