What are these covers for?

[wildsump]

I came across these covers in a box a friend was going to throw away. I have been searching trying to figure out where they belong. What might these be worth?

 

[consol]

speakers plate i think

 

[g8rpi]

Look like they belong in the bottom of a urinal or sink.

 

[portland_bill]

I've definitely seen them before, a long time ago, but am struggling to think where.

Could they be intake grilles on the front of a 500 or 600?

 

[martingail11]

I think, these may be speaker’s plate.