Yup, I would try to do this without calling a lot of attention to it. You're not doing anything wrong, but I can tell you from experience that just by leaving a message with our Principal about early admissions into first grade caused her to contact the assistant (now current) superintendent.
Does your school district have a web site? You might find all of your policies online. Also, your local library should have the policy as this is supposed to be something of public record.
Also, you don't have to ask specifically for the policy on acceleration. You could just ask for your schools published policies. Probably a nice thick binder like ours

JB