As with automotive there is a restriction of no child seats in the front. The middle row seats should have been configured with an additional buckle (black, webbing only, w/no activation switch) which would be used in place of the standard buckle to disable the airbag for the middle row seats. The front 4 seats are standard with airbags in the 206 and the bench seat was an option. If the request is related to the bench seat, there was not a request from Cessna to provide for the deactivation buckle for the bench seat as standard equipment.
You should be able to order thru your Cessna Service Center or CPD2:
LH - 7035-2090112396
RH - 7035-2100112396
