Can you please confirm that the SPAD array window is the one closer to the mounting holes (i.e. further from the electrical connections)? My guess is based on enlarging the image 2/5ths down on your product page and comparing it with the drawings on page 26 of the datasheet. There’s a teeny tiny square surrounding one of the two circular imprints on the face of the sensor.
Yes, you are correct; the SPAD receiving array is the lens closer to the mounting holes.