The press release says it was related to independent CNG kit supplier. So Toyota Indus themselves must have got the replacement free of cost from the CNG kit supplier.
Moreover due to this problems their cars might have started blowing up on CNG like bombs. So I would say a wise move by them and not a courtesy call.
There is no such thing as "customer first" in corporate world. Its all about $$$$
A friend of mine had the popular "coure gear shaft noise problem" in his coure 06 but indus motor never agreed to replace the part although they accepted this is a generic problem.