Hey Doc or other helpful souls out there ...

'92 400e with some bulbs out. I unfastened the taillight assembly and found the following ... they are the same on each side meaning there are 6 receptables for bulbs EXCEPT the driverside assembly has an 8 prong pin with 6 of them wired and the passenger side has a 6 prong pin with only 5 wired. Long way of saying the driverside has one extra tailight. Is there some explanation for this?