Every COM interface must derive from IUnknown. Which provides essential services: memory management (AddRef and Release) and the ability to discover other interfaces implemented by the COM object (QueryInterface). The v-table for a COM interface therefore always starts with 3 function pointers to the implementation of these methods. The actual names of the functions or what language they were written in do not matter at all, COM only cares about the function pointers.
You can name the implementation functions anything you want. Intentionally not using the IUnknown function names is unwise.