I didn't see any obvious differences between the two in the menu.

There where 2 independance battles, but the latter battle wasnt really much of a battle, it was fought by kids whose ages where averaged at just 14/15 years old for the British Army.

The difference is that one is named "War of Independance" (with an a instead of the e you used in the title).
Probably was part of a patch and noone noticed that that file was there twice.