The Spanish pdf document linked here lists all countries of Latin America and the Caribbean that ratified the "UN Convention on the Rights of Persons with Disabilities" (CRPD). You will find the date of the signature and the date of the ratification - of the convention and the optional protocol. Countries that are not listed didn't sign the convention as of November 2017 (date of compilation of the data). The document also provides a link to a graph / world map containing the same data.
[Abstract: Editors of Education Worldwide]