Good Afternoon from Ireland. I have been offered a S&W revolver ie a 686 with 4 inch Barrel/Stainless steel/6 shot/ 38 Sp and 357 Mag /Non wood grips. With the synthetic grips I think it might be no older than 1994. Its serial No is CEZ 7271. Its cylinder is a bit dusty-discoloured . Any way to check its age and use ???? Regards john.