Help identifying pre-war parts

[Robert Lees]

Any ideas where these go? Screws are sprung-loaded.
(I'm not too familiar with pre-war aircraft)

About 9" x 9"

[Ragwing nut]

nothing I recognize

[3Dreaming]

Looks like maybe a home made winterization plate for a closed cowl airplane. Other than that I am at a loss.

[Robert Lees]

Looks like maybe a home made winterization plate for a closed cowl airplane. Other than that I am at a loss.

That makes sense! Perhaps a means of preventing birds nesting in the cowl?