I can only speak for the Microsoft installer, but if a newer version already exists on the install computer, it will not overwrite it, as most of them are backwards compatible. And most of the standard files already exist on current operating systems. When a file is required to be installed in the %WindowsSystem% directory, the operating system itself will detect if a file is 32 bit or 64 bit, and install it in the appropriate location. The only issue that I have run into is with databases on Windows 10. MDAC cannot be installed on Windows 10, but all the necessary components are already there. They just might have to be activated. Don't ask me how, because I have found Windows 10 to be a convoluted nightmare that I still haven't completely found my way around.

J.A. Coutts