By the way - a 504 is to cover accommodations for a MEDICAL diagnosis. The child's grades should not be a factor in the matter.
Just because a kid with terrible asthma is getting A's, doesn't mean they don't need a 504 for accommodations regarding physical activity. Just because a kid with PTSD gets A's doesn't mean they don't require accommodations. Same for ADHD! If you want a 504 you need to submit a request, in writing, asking for an evaluation.
Personally, I would want to go into the ARD meeting (or whatever they call the acceptance meeting where you live) with paperwork in-hand from a private neuropsych or psychologist.
What is an ARD or acceptance meeting? Believe me, the school has been totally ridiculous in the situation with both my kids. The school psych told me that if DD is doing fine in school and her learning isn't impacted (which according to her, it isn't because she does so well on achievement tests)she does not qualify for a 504. I informed the psych that they need to evaluate DD based on her medical diagnosis (ADHD) on how she is WITHOUT any modifications (like the meds) and that this is federal law. She said she wasn't aware of that (!!!!). But it still boils down to "no modifications are needed at this time." The teacher did not help, claiming that DD was "perfect" and she didn't see any issue with her. The school psych went in and observed her one day for 45 min. (probably when her Adderall was fully kicked in) and then told me she didn't see any problems. So I let it go. Then the last week of school I got an email from DD's teacher saying that DD is sloppy, moody, excessively slow, can't accomplish the simplest tasks, etc (this after she claimed she was "perfect"!!!). I forwarded that onto the school psych with a note "maybe she needs a 504 after all" and of course the psych never replied, which is typical. We switched her meds over the summer and so far the new teacher doesn't have any complaints. I'm not sure what I'd ask for in a 504. If I took her off her meds, then it would become painfully obvious to everyone that DD has major issues (and her current teacher did see that one day when I ran out of patches), but if she is overall fine on the meds, then I'm not sure what the 504 would address (other than the CogAt).