In broader terms, should a school's demographics (or perhaps standardized testing scores) be taken into account when deciding whether/how to advocate on behalf of your child?
While some schools may try to promote this idea, touting that they teach all subjects one year ahead, therefore there is no need for a gifted program... my answer to your question is, "No."
The simple reason behind this is that all gifted children are not alike. When advocating for an individual child, the idea is to match a program to your child, not to match the child to a program.
To expound a bit on "matching a program to your child", this begins with understanding the child's needs well including what s/he already knows, what s/he is ready to learn next, and what methods of teaching/learning are most effective/helpful/productive with that child. Advocacy focuses on creating/developing/proposing options which will comprise a custom program which is a good "fit" for your child's needs, while operating within budgetary constraints. For some students, this may include independent math work through AoPS, for others this may include single-subject acceleration of 1 or more years in math during which the child attends math class with children of a higher grade level. Other students may benefit from whole grade acceleration. These are just a few common examples. The book
Re-forming Gifted Education is a helpful resource for planning and advocating.
The opposite approach, "matching a child to a program", is more like a predetermined solution seeking a problem. For example, a school might decide that "gifted math" will consist of math 1 year advanced and then seek out students who might need or benefit from that program. If this narrow solution does not match your child's needs, then your child is not accepted into the "gifted program".
