can I change the root domain name of my wpmu site?

My site is hosted on a shared server where I get a number at the front of the shared server, i.e. 43.b.server.me. When I post links from my site to FB, the base of the server address, b.server.me, is flagged as spam. I would like to change base domain over to mydomain.com. Is this as simple as parking all my other domains on mydomain.com, editing the wp-config setting to mydomain.com for the:

$base = '/';
define('DOMAIN_CURRENT_SITE', '43.b.server.me');
define('PATH_CURRENT_SITE', '/');

to read:

$base = '/';
define('DOMAIN_CURRENT_SITE', 'mydomain.com');
define('PATH_CURRENT_SITE', '/');

thanks