I agree there should definitely be an actual HTTP header provided by the server, but I wouldn’t advice replacing it entirely. The Content-Type/Charset meta tag should still be specified in the HTML, if only as a fall-back. Serious issues can come up if neither the server nor the HTML provides a specific charset.
(And you never know if/when the new guy will accidentally screw up the server config.)
HTML5 even has a short-cut meta tag for this purpose:
<meta charset="UTF-8">