yes it matters, LOL, to the costume designers. Because during 1699, a commodore wore a completely different uniform than in 1700, when the British crown re-designed the uniforms for all officers of royal navy, yet again...
So the way the Commodore is decorated in 1, shows that the film was set prior to 1700, though it very well could have been 1699.
The way Beckett is dressed is slightly more modern, but officers of the EITC were businessmen and not government officials, so they wouldn't be wearing the uniform. However, the way Beckett's coat buttons, as well as the detailing on his sleeve, suggest a Parisian rather than a Londonese look, which was common for British citizens who were living aborad. Aka, Beckett has probably actually been living in India for some time prior to 2.
When it comes to the timeline, I'm not sure how accurate Ted & Terry always are. For example, if you read the draft script, I think there's a mention, isn't there, of a steam ship, because Norrington makes a comment about how the world is changing, and Gov. Swann refuses to believe it is for the better. If this is the case, then Ted & Terry have committed a major faux pas, because those kind of ships weren't around until the very end of the 1800s, and 'Pirates' has thus far been portrayed as being set as much earlier. That's just an example to show that the timeline may not be their first priority.
However, I think I may have narrowed it down. The official East India Trading Company was set up in the year 1600, and largely came to power under Queen Elizabeth I and 'privateers' such as Francis Drake. However, in 'Dead Man's Chest' if you look quickly at the Letters of Marque, which Beckett possesses, they are signed by King George. I checked the official portraits and dates of the various Georges, and I think that the most likely candidate is King George I. He lived from 1660 to 1727, but his actual reign only lasted from 1714 to 1727. There's no hard evidence that this IS correct, but the fashions are similar, and this is before England lost its hold over the Americas. Also, as we move into the late 1700s and especially the 1800s, piracy starts to lose its influence much more. Also remember that Jack was branded a pirate for refusing to transport slaves, and the 1700s were a hotbed of years for the buying and selling of black slaves, until the emancipation of slavery in Britain in 1772. So, I reckon the reign of George I for the movies (1714-1727).