I am flying on the TK0720 flight from Istanbul to Bombay. This is a B777 and the SeatGuru Seat map as well as the TK website say that Row 40 is an exit row.

https://www.seatguru.com/airlines/Turkish_Airlines/Turkish_Airlines_Boeing_777-300_V3.php

However just a few days ago I flew the reverse flight TK0721 BOM to IST and got myself Row 43 as an exit row. I believe this is the same flight that serves both directions. I'm confused. Are there two seat layouts? Is the Istanbul to Bombay flight special somehow? Anyone know whether row 40 is an exit row or Row 43? Would love to select the right exit row since this is a long 6+ hour flight.