Vtg GF Gold Filled Heart Pendant Necklace Delicate

Vintage delicate chain with heart pendant. The back of the chain is stamped: 1-20-12kt gold filled. I do not see a marking on the pendant, but they appear to go together. Some of the gold has come away from the pendant. The closure has a very small lever on the side... not sure if it's made that way or not, but it's still functional. Please view all photos before purchasing.