The developer pack doesn't have anything to do with an SDK. It just contains the reference assemblies that you need to compile a project that explicitly targets 4.5.2. Without it you couldn't select 4.5.2 from the Project + Properties, Application tab, Target framework version combobox.
The reference assemblies in the C:Program Files (x86)Reference Assemblies directory normally are put there by the VS installer. But 4.5.2 shipped too late to have them available, nor is it covered by the Updates.
Do keep in mind that it is very rarely useful to target 4.5.2. It has exceedingly few new additions to the framework, it is mostly a maintenance release. Not unlike 4.0.1, 4.0.2 and 4.0.3, also widely ignored. If you do target it then you're likely to force your user to update their .NET install, it isn't being distributed by Windows Update as yet.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
