Hmmmm. That is a good question. All of the older tins from around that time say "Made in the UK in association with Dunhill Tobacco of London". Also I believe that Lane Limited was the US Distributer at that time.
I'm not sure if any of this information helps at all. Sorry.
Unfortunately even if you know for a fact that the tin was made in 2005, you still don’t know who made it solely judging by labels. That was the year production shifted from Murray’s in Belfast (Northern Ireland, UK) to Orlik in Denmark. They also sent the unused lids to Denmark so for a time the blends produced in Denmark were in tins that said UK. If it was 2004 you’d know it was Murray’s, if it was 2006 you’d know it was Orlik. 2005 is the only year that could be either. At the time I remember some people claiming that you could tell which was which by the ring on the bottom of the tin (or lack thereof) but I never quite understood it.