Wrong survey number in farm land boundary

Hello sir/madam, I have a farm land in Tamil Nadu which was bought 13 years before, we found survey number of one of the boundary wrongly mentioned. Instead of 167 it was mistyped as 161, but no change in any other matter in the document. We are looking at correcting the same. Need your advice on the following 1. Both parites who signed while selling are not alive. And there is no legal heir documents available with their sons/daughters 2. Does it require registration or can it be done as a correction? 3. Should we go through the court for the correction or can it be done through the sub-registrar office? Which one is recommended and cost effective? 4. Also one of the boundary mentions name of the person who owned the land before 1990, it changed hands in 1990. Should we correct to reflect the current owner name? Or it is fine to retain the same name as it is in the parent document? Please suggest. Thanks