The contractor says the work meets code, doesn't that end the dispute?

No, and this is a common misunderstanding worth correcting directly. Building code compliance represents a legal minimum floor, the baseline level of safety and construction quality required by law, not necessarily the specific standard of quality, material, or finish that your particular contract actually promised you. Code compliance and contractual compliance are two entirely separate questions.

If your written contract specifically called for a particular material, brand, or finish, and what you actually received instead was something different, even something that technically satisfies the building code, the code compliance argument doesn't answer for that specific contractual gap at all. Your claim in that situation rests on the terms of your contract itself, not on whether the finished work happens to also clear the minimum bar set by code requirements.