That will give you Unity 4.5 though. If for some reason you want to stick with 4.3 and you want to download 4.3.4, you can get it from https://unity3d.com/unity/download/archive
That is exactly what it doesn’t do! Currently I have 4.3.4f1 installed, newest version is 4.5.1. And yet the “Update check” tells me my Unity is up to date.