What is this parts in Aiwa J400?

I grabbed this picture from eBay. What are the two small plastic parts in black? I have these with my J400 MKii as well. I have fully restored my J400, but never figured out where to install these two. The player works fine without the two pieces though.

 

You might have to look up a service manual to locate them.

 

Found where they belong to… on the door plate to help push down cassette when door is closed. It’s indeed drawn in the service manual, however not separately noted, so I never paid enough attention. I don’t see the same design on later models. Finally my J400 is 100% fully restored