Yes.
Boeing has produced several service bulletins. All the design changes that were introduced were introduced via service bulletins produced by Boeing. Those service bulletins are the vehicles to convey the information to the airlines to either install modifications or, in the context of your question, to carry out specific maintenance actions.
In addition to that, in Transport Canada's case, the oversight of the airlines themselves is conducted primarily by our national operations branch, which oversees the airlines that actually fly the 737 MAX. There are three of them. The maintenance activities prior to re-entering services would have been overseen and checked by that other part of Transport Canada that has that as their mandate.