With the merlettes it's gonna be pre- 2000 or so.

Maybe a tedious trip through www.ehubcap.com - center caps.

 

Those are pre war, late 30s or early 40s

 

II think 30s as well. This might help. You can also check the dealer brochures at The Old Car Manual Project. The Old Car Manual Project

Just go to google Images, select Tools, select Large images, and start checking each year. Here's a 32:

 

This should help. Bookmark for future use 😉

Cadillac-LaSalle wheel covers and hub caps