Not as nice as the real thing, but it gets the job done. Looks like you can even do this with the origianl RPi’s too.
https://www.instructables.com/id/Google-Assistant-on-a-Raspberry-Pi/
Oh and go here for adding a button to it
https://www.instructables.com/id/Button-Trigger-for-Google-Assistant-on-the-Raspber/