Please speak up, but obviously don't be a jerk about it! You will be teaching your kid that a) it's ok to speak up for yourself, and b) that everyone makes mistakes and it's important to find a kind, diplomatic way to let people correct them.
It goes without saying that this is not to say your should demand recognition all the time and for minor things. But if the kid worked hard and achieved a set goal, by all means, recognition is in order!