Yes, this matters because you need to have credit for all of your required math classes in order to meet graduation requirements. This situation can also negatively impact future class scheduling if you are missing a math prerequisite for a class in which you trying to enroll.
The most common situation where this occurs is when a student receives a marginal score on their AP calculus test. Currently, if you receive a 3 on the calculus AB test, you are allowed to enroll in calculus II (MA 2160) but you will not receive credit for calculus I unless you receive a C or better in calculus II. There are similar rules for the AP calculus BC test. Go to the Admissions AP, IB, and CLEP Scores page for the latest information on these requirements. They are listed on the required scores page for AP credit.
If you find yourself in a situation where you are missing credit for a required math class then contact your academic advisor ASAP for assistance in resolving this issue.