DOES LIMITATION HELPS IF GEN PURCHASED LAND FROM SC 34 YEARS

Sir, My mother is general caste...And second wife of my father who is sc. In a judgment of district court...The court cancelled an agriculture land issued to my mother by sc citing that her caste certificate of sc is of bihar and that caste is general here.that matter was running in high court...Since my mother had negotiation with other party...We withdrew the appeal. Now my mother who bought agriculture land from another sc via registry in 1983 filed a case to nullify the registry and want land as the lower court verdict says my mother is general here.we have a house built on that. Kindly guide.does limitation help?