Yes or No. It does not support wrapping C style DLL directly.
We would want to focus on only C++ DLL for now because there are already such tools like PInvoke Interop Assistant can be used to generate .NET wrappers of function P/Invoke for C style DLL exporting functions only. And there are no other tools which can generate .NET C# Wrapper for C++ DLL automatically without developers’ manual involvement, such as writing extra C# code or script code, so working with C++ DLL is our highest priority.
If you really want to create C# wrapper for C style DLL using xInterop NGen, a simple work-around for you is to create a simple C++ wrapper class to call all the C style methods. This is actually very simple, your probably can wrap up dozens of methods in half an hour.