If it’s an upper case “L” and also a reduced case “c”, it’s for Louis C Marks who made jewelry while in the 40s. SETA is a corporation that provides fashion jewellery. Their jewellery typically provides a CZ plating about silver. CN implies that the jewellery is produced in China, https://bolaonlineterpercayacaspe02234.livebloggs.com/43484440/the-fact-about-jp88-that-no-one-is-suggesting