Seatguru does not appear to feature details of AVOD equipment mounted in your footspace.
Took Malaysian 747-400 in Y last week and in the 3-across window banks the box, notably large, was mounted under the centre seat (B and J). Seatguru says nothing about this. I have not noticed the boxes under centre seats before, am used to seeing them under aisle seats. Sensibly, it not being a full flight, Malaysian had corralled the single travellers together in that cabin and allocated them window and aisle seats with no centres allocated, so it was not a problem, but would be a notable inconvenience on an ultra-long haul in Y if that was in your way.
Could these boxes really not have been put anywhere else ?