Gamepads and other input devices already only send “raw” events, because the operating system makes no attempt to try to map them to a “virtual” key.
I’m not sure why you would want raw mouse events. A click of the mouse button is a click of the mouse button. The only thing this might circumvent is the remapping of which is the primary/secondary button in the operating system, but I’m not sure that we can portably get this information.
Can you think of any scenario in which the above causes problems?
Put the xinput1_3.dll file anywhere on your PATH (eg. in the Panda3D bin folder, or in your system32 folder).