Can transfer of Title happen without registration?

Village Pune. One Mr. ABC (Hindu) was owned a land in the year 1970. The said Mr. ABC has gave an application to the Revenue Officer that, the names of his Grandsons i.e Mr. DEF and Mr. GHI be recorded to the 7/12 extracts in his place. Merely on the basis of the said application, the Revenue Officer has mutated the names of Grandsons i.e Mr. DEF and Mr. GHI to the 7/12 extracts and the name of Mr. ABC was deleted. This was the general practice in Maharashtra in old days. So please tell me, whether the said Grandsons i.e. Mr. DEF and Mr. GHI has legal title in the said property or not? Or any legal provisions or decision of the courts which shows that the said Grandsons i.e. Mr. DEF and Mr. GHI has legal title in the said property. Thanks