Vent cover for Whirlpool #YWML55011HS?

I purchased this otr Whirlpool microwave used. Sellers had it vented and I need it ventless, which means this part (in the pic) needs to be removed and covered with a part that I’m guessing was originally attached.

I watched unboxing videos on YouTube to see how it came otb new and couldn’t tell if it was in there.

I can swap it out myself if I have it.

Does a cover come with the microwave new?

How would I get just the cover?