was it self acquired property of your grand father ? was gift deed executed by your grand father? how id your grand mother gift house to your grand father ? was it by gift deed duly stamped and registered?
if suit had been filed in 1999 it must be ripe for hearing since 15 years have already passed . what is pendency of cases in your city?when did your uncles come to know about execution of gift deed?
without going through the plaint filed by your uncles we cannot say that suit would be barred by limitation . having said that it is always better to arrive at an out of court settlement particularly so when dispute is between family members