From some Poirot-esque Googling, I reckon they can't have been manufactured in 2003:
Most of the gushing reviews - talking about how the Sessantas are the cynosure - are from 2006 or later.
Also, the blurb about the tyres mentions they were called Sessantas to celebrate the 60 year anniversary of Vredestein's Enschede factory site (sessanta is apparently Italian for sixty). Wikipedia talks about the company as-we-know-it starting life in 1946 (although related businesses were around since 1908)...
So, 1946 + 60 = 2006, which coincides with the first reviews and gushing user reports. If this is right, your tyres must have been manufactured sometime during or after 2006.
Most of the gushing reviews - talking about how the Sessantas are the cynosure - are from 2006 or later.
Also, the blurb about the tyres mentions they were called Sessantas to celebrate the 60 year anniversary of Vredestein's Enschede factory site (sessanta is apparently Italian for sixty). Wikipedia talks about the company as-we-know-it starting life in 1946 (although related businesses were around since 1908)...
So, 1946 + 60 = 2006, which coincides with the first reviews and gushing user reports. If this is right, your tyres must have been manufactured sometime during or after 2006.