Yes. The doc-comment is even explicit about this:
/// Updates the initialized element at `index` to the given value.
///
/// The memory underlying the destination element must be initialized,
/// or `Element` must be a trivial type. This method is equivalent to:
///
/// self[index] = value
The same is in the other initialization pitch. There, I addressed your question as follows: The proposed changes "include a method to update a single element. Evidently that is a synonym for the subscript(_ i: Index) setter. We hope that documenting the update action specifically will help clarify the requirements of that action which, as experience shows, get muddled when documented along with the subscript getter."