Buying a plot approved by BMRDA

Hi, I am planning to buy a BMRDA approved plot from Celebrity Prime Developers Eco Front Properties in Anekal Taluk, Karnataka. After reviewing document, it was found that Land belonged to owner's paternal side grandfather(who has passed away in 2011, have provided death certificate) and through GPA he possesses the land and through joint venture he and Celebrity Prime Developers have made this layout (The layout itself has been approved by legal authority). GPA Details: Not registered only notarized From his only paternal side uncle (59 years old), paternal side Grand mother (81 years old) and his own brother (35 years old), giving authorization to landowner to completely posses the property and to further develop or sell the property. RTC : Details: Latest RTC records shows that property in Mutation records shows up the landowner name only. Historically it was showing up as his Grand Fathers name and later both Grand father name and Land owner name started showing up and eventually only Landowner name is showing. Question is since land is passed to landowner via GPA , is it fine to buy this plot? Thanks, srinivasa