Significance of NOC if property came to nominees questioned by heirs

My grandfather died without will. All the 6 uncles and my father filed a no objection certificate in 1986 if the flat is transferred to my grandmother and further no objection if my grandmother makes my father and uncle as nominee of the said flat. The society transferred the flat to grandmother. A nomination form was filed by my grandmother stating that 'rights, interest and title in the flat should be transferred to the 2 nominees'. Post her death in 2003, the society transferred the flat in the name of the nominees (my father and uncle) by endorsing the share certificate. In 2015, all my 6 uncles have filed a petition for letters of administration for the said flat. The same is based on the fact that they had only made my uncle and father as 'nominees' of the said flat as per sec 30 of Maharashtra Co-op Societies Act and not made them owners. My queries are as under: 1) Is the case barred by limitation? 2) Is the right of the legal heirs maintainable in view of NOC filed by them