are you saying that "since VIN nunber 5D639631" that it became programmable, and that it was no longer an RC5EC5 but was from then on an AB Autoliv?
I think that's what you are saying.
Exactly. In case of RC5EC5 you have two different airbag ECUs one for single-driver airbage, one for double airbag. In case of Autoliv airbag it is only one programmable airbag ECU, starting from VIN number 5D639631.