Yes, it's gold plated sterling silver. It's difficult to see in your pics, even when enlarged, but I presume the earring has (or once had) one or more small stones, or perhaps is pavé set with them. Jewellery is often marked 'CZ' as an indication that the stones are cubic zirconia, not diamonds.
A lot of Kiera jewellery also carries a 'VN' mark, but I've never seen an authoritative explanation of what it stands for. Presumably it means something to Kiera but it's not a 'universal' mark recognised across the jewellery industry.