I would recommend using this link below, the one you referred to is out of date for 1.10.
https://fmod.com/resources/documentation-api?page=content/generated/engine_new_unity/script_example_programmersounds.html#/
The GetRaw function has been replaced with a ‘handle’ member variable.
The previous constructor took in an IntPtr, which as you suggested, you will need to set after creation if you want to overwrite it.