Nope unless you finish it in normal level and then there are usually extra points for finishing it in hard mode.
Some of the points take forever to get like in Ghost Recon there is 25 points for 10,000 kills in multiplayer (That might take a little while)
Once you have a game you can check on the menu for the list of achievments and what they are worth.
Or check here
http://www.xbox360achievements.org/