Vintage Gillettes made in the USA and Canada have helpful date and serial codes which let you figure out the date they were produced. AFAIK British Gillettes do not have codes and can only be dated to general production time periods for each particular model. Do modern razors have date codes? That is, if I pick up a Merkur, Muhle, Edwin Jagger, Parker, etc. is there any stamp/marking on it that will let me figure out when the razor was made?
Nope. They are not constructed to last anywhere near as long as a vintage Gillette, therefore any means of dating would be irrelevant.