Hi Kasukur
1- The public and private Dll depend on your software to be known . If your software done in your house , you can just ask the Developers team which function and class are private and public .If the software out your house production it will be difficultly to know .
2- You can have only one framework in your machine ,in your case 4.5.2 , so Vgen will see only this framework and Dll
One of major issues with framework to have more than framework installed in the same machine .