Read the stamp
EPC silver mark
For an EPC silver mark, a separate crown or shield may be a trade device. EPC commonly means electroplated copper on silver-coloured wares.
Copper as the base metal
EP describes the coating process and C the copper substrate. Worn high spots can expose a copper-coloured base, while the maker name and model number identify the manufactured piece. The letters give a construction description rather than a sterling grade.
What to check next
Compare the complete stamp with EPNS and EPBM, whose final letters name other base alloys. A separate crown or shield may be a trade device. Use the company name, not EPC, for a maker lookup.