Reasonable 504 Accommodation?

Hi there.

My child was in kinder when Covid hit and then had home study for about 1 1/2 years. He was obviously ADHD from a young age and we started working on a 504 plan about 3 years ago. It's been a great experience and his needs are becoming less and less since we've learned cognitive based approaches to regulate his attention (and also medication) and he's an honor roll student every quarter. At his current school, he doesn't have to wear collar shirts as long as he wears t-shirts that are "spirit wear" for the school. He still has some pretty serious sensory issues, collared shirts being one of the main things. Even mostly unbuttoned polo shirts make him feel like he can't breathe and are super constricting. The one time he had to wear a collar shirts, he cut the collar off in class. He goes to middle school next year and they require collared shirts (polos) every day of the week. Is it reasonable to ask that his sensory issues be added to his 503? I'm more than willing to to buy school sponsored shirts and he will follow every other part of the dress code. I just found this out last night and I'm wondering what our options are. Would this be considered a reasonable accommodation? It's there another sub that I should ask this question on? I appreciate any feedback you're willing to give!