Your item can be dated from within the period 1927 through 1933, inclusively.
Scroll down the source page to the area marked FROM/TO/Descriiption Year Markings | Plomb Tools!
The exact year of manufacture is within the numbers below "Los Angeles"
Don........
You know I don't think it is the top of a key but im not really sheer what it is. And the area below the los angels is almost all gone would you know what it is by any chance.