2017 Service Park Assist sensor

My 2017 Volt was having some problems with the FPA sensor. A good wash used to fix this, but now it has shut down the entire system. I pulled the sensor out to match up the part number to ensure I ordered the right part. Unfortunately, the part number (23228941) does not match up with the GM part number. Neither does the sensor in the grill (23247086).

So GM lists parts 23370671 (inner) and 23370672 (outer). The front bumper has 6 sensors: 2 in the grill, 2 at 45, and 2 on the wrap around. If I am replacing one at the 45 position, is that inner or outer and does it make a difference?

TIA.