6 pins. At a guess i'd say that the square pad (bottom one of the column of 4 pins on the left) is GND. I'd also hazard a guess that the 2 pins on the right are for the emitter LED and that R336 may be the current limiting resistor for that LED. That leaves 3 pins. One will be some sort of supply - probably 3V3 or 5V. You could see where capacitor C213 connects to in case it's a decoupling capacitor. That may indicate the power pins.
That leaves R333 and R337. Are they the same value I wonder (i.e. same number printed on the top)? Could they be pull-up resistors for an I2C device?
I should have asked this earlier, but is there any writing on any side of the sensor itself that may hint at a part number or manufacturer?