Not quite; it was partway into 4e's online-magazine run that they did the player/GM split. There were several monster articles in Dragon all through Paizo's run, and even into the online era.
Personally, I prefer player material and setting fluff (like the Eye On) articles to be in Dragon, with GM-centric material (including but not limited to adventures) to be in Dungeon, but right now I'm just happy for the consolidated magazines. :/