There are more fake chain watches in the world than there are original. Some fake chain watch are even sold at an outrageous price. Here are some tips in identifying a quality chain watch:
Original gold watch is usually not magnetic.
Pay attention to details. Assess where the inscriptions are made and check the weight. Original chain watches are heavier.
Check the authentication stamp that it is gold or silver.
Check the placement of the logo and brand name if it is the same with the samples on the watch website.
Investigate the mechanism of the watch: if it is Quarts or Mechanical.