Vintage WWII Sweetheart Heart Locket Homefront w/ Photos US Army Gold Filled?

Vintage WWII Sweetheart Heart Shaped Locket Homefront w/ Photos US Army

The heart pendant itself has no visible markings to indicate it is gold filled, however, the chain is marked but I cannot make out the markings to see if it is gold-filled or not. It appears to read "LS Company" at the top, whom had made many gold filled watch fob chains, pendants, etc, but I cannot make out the markings on the bottom loop underneath "LS Company".

Since I cannot ascertain If it is indeed gold-filled, please purchase with the assumption it is NOT gold filled.

Shows signs of age and could use a good cleaning