The student usually does not need to ask the "lecturer" anything about how to prepare for the course. The student needs to have (hopefully recent) credit in the prerequisites for the course. If the student is in doubt after being informed on the prerequisites, then the student could ask the "lecturer" of the intended course.
My own opinion about something like fundamental physics of Electricity & Magnetism is that merely having passed your Calc II course might not be enough to perform well in this E&M course. Having more mathematical applied maturity with the Calc II and analytical geometry are very very useful in ensuring good success and good learning. You would believe that the prerequisite courses are enough - but not always if you are weak at solving analytic geometry and calculus problems, or if you are still inexperienced doing so. For me, E&M at that level was a struggle. I could have done better if I would have repeated it, since I also restudied Calc II. In short, prerequisite course credit alone is not always enough.
It is still up to you if you want to discuss how to succeed in the course with the "lecturer" (I assume you mean "instructor" or "professor").