Changing my (facelift) seats for sport seats from a non-facelift car, there is an extra sensor on my old seats -- what is it for? do I need it?

Could it have an impact on airbag codes or issues? My car has side airbags, would that be a problem? it's one of the RARE car with side airbags, which sounded like a great idea at the time! It has special card doors for the side airbags, and possibly that sensor as well.Looks to me like the electronics box to do with the 'seat occupancy sensor'. It controls whether the passenger airbag deploys based on if there is a passenger in the seat.