That is how I recall it. And IIRC the Ruck, Ruck-rover, rover and centreman were, as a group, known as "followers" because they followed the play around the ground, while everyone else more or less stuck to their positions.In the olden days AFL footballers playing in the midfield were known as Rucks, Ruck-rovers, Rovers, Centremen and Wingmen.
I don't know when "midfielder" became a thing, but it was post the "ruck-rover etc" stage.
I'll admit I've always thought of "midfielder" as a name for the 4x "middle" players, excluding the wings, but it makes sense to include the wings in the "midfield". And it certainly makes sense when you start talking about "inside and outside" midfielders.