Is sale valid without traceable GPA when owners signed as witnesses?

Is a sale GPA mandatory when the GPA holders also participate as ordinary witnesses in the sale deed? In a Mysore State Government Inam land case, the land was granted to K.C. Ramaiah by the Deputy Commissioner through a Grant Order. After his death (death certificate unavailable), his wife and three daughters appointed K. Muniswamappa as their GPA holder, who sold the property to C.A. Narayan in 1971. The wife and daughters participated in the sale deed as ordinary witnesses along with the GPA holder. Since then, revenue records have been continuously in the name of C.A. Narayan, and all subsequent transactions are clear. However, the GPA document in favor of K. Muniswamappa is not traceable, and the advocate is raising concerns regarding title clarity, as the sellers signed only as witnesses and not as consenting parties.