Can you identify this mysterious pachislo part?

[RVideo]

Well after two 'delivery exceptions' blamed on weather (lol), the Hanabi Fireworks has finally arrived. Installed the autostop thing, the speaker pots, and reset it. There was an error (wow they really know how to alert you to 'an error'), and as it turns out, the pins for the hopper were bent, so I carefully bent them straight again, and it was all good.

This is a really cool machine. There is a small black tray looking plastic piece that was loose, laying in the hopper. It is, oh I don't know, about 3 or 4 inches across. It bears resemblance to the plastic handle inserts on the side of the case.

I cannot for the life of me figure out where this piece goes.

Also, sometimes the tokens do not fall in the hopper, but off to the side, in particular, when adding a token when the wheels are still spinning.
Is this normal?

Sorry for the noobish questions. i will try and post an image if you dont have a clue about the black plastic piece.

Thank you