Guys,
I have lost a plastic part and not sure if its even needed or not. It is the platic insert for the P4 arm at the end. Is there a way to get these? Do not want to send it in for just this. Thanks.

You don't need these plastic pieces, some of the types of prop guards fit into these spots and some fasten another way.... they can all be removed if you like.

As noted above they are removable and the slot is used for the quick removable type prop guards.