Validity of GPA in India that was notarized in US by public notary and endorsed by Indian Consulate

Me and my wife are currently residing in USA and co-owner of yet to be registered apartment in Bangalore. We got a call to get it registered. For this purpose my wife would be travelling to India to get it registered. As I am also one of the joint owner, I have drafted a power of attorney in my wife's name and got it notarized by public attorney here in states. I have not taken any witness signature in the document. I am preparing the document to be sent to the Indian consulate to get it endorsed (this is as per Indian consulate requirements to send them notarized copies of GPA which they will attest and send back to us via post). Per the plan, my wife would carry to India, the endorsed GPA, and will get it registered at sub registrar office in Bangalore. My query is 1. Would this a valid GPA without witness endorsement? Is witness endorsement is also a mandatory criteria at the sender end (in my case in US) or the witness is needed only at the time of executing the GPA in sub registrar office? 2. Few friend's mentioned that GPA needs to be sent to India via post only to attorney address and opened at the time of execution of GPA in sub registrar office. Is it a rule or it depends on state to state? Will my GPA be invalid in case my wife carry with her to Bangalore?