There are two ways I can think of:
Your installer must extract the Visual C++ Redistributable packages somewhere prior to installation. Usually it's put somewhere under
%temp%
. You can either clean that folder prior to installation, or run the installer on Sandboxie and then browsing the sandbox files to find it and check its digital signature.Install a HIPS (Host Intrusion Prevention) software, set it properly, and you'll be prompted for every package installation individually.
If you'd like to check the VC++ Redistributable DLLs already installed on your system, browse to %windir%\System32
and check the msvcpX.dll
files (where X is the version number (ie msvcp140.dll for VC++ version 14.0.23918).
And kudos for keeping the good practice of checking digital signatures before granting full rights.