FWIW, I grew up in the era of alphabetically seating. My last name started with W. I was always in the back. It didn't have an impact on my education--- 2 ivy degrees and a professional career.
If anything, by the time the teacher arrived at my row and asked me to give a speech or answer a question or read aloud, I had already heard the mistakes the other kids had made.
On a more serious note, if your child has a vision issue, or ADD, then make sure he/she is up front.
If not, I'd just relax and let him enjoy his K year. The other kids are gaining no advantage by sitting up front, if that is your concern.
I don't think it would have ever occurred to my parents to intervene, and it would not occur to me.
Pick your battles...this does not seem to be one of them.