Rear seat belt buckle for power headrests

[bymep]

Would someone happen to know the part number for rear seat belt buckle that has electrical connector to use with power headrests? RealOEM shows same part number for with and without electric rear seat. The buckles look the same but one has a pigtail coming out of it and another one doesn't. Can the pigtail be added separately? This connector sends a signal to the headrest module telling it that the seatbelt is buckled which causes the headrest to go up.