Hello Charlee,
No, it hasn't got a metal cover for the side compartment, but the grooves are in the base to take one. I don't know whether it had one and it was lost, or it never had one in the first place. Seeing as it dates from 1940 perhaps this was an economy measure.
I love the wooden cover on your compartment. My 1916 99K has exactly the same base and case.