If you have a message with wikitext in it, you can parse it with the mediawiki.jqueryMsg module (if it's very simple wikitext, e.g. internal links). Now think about messages with paramaters, i would assume, that these parameters are parsed, too. Here an example:

mw.messages.set('test1', '[[Special:Block]] $1.' );
mw.messages.set('test2', '$1 test.' );
mw.message( 'test1', 'test' ).parse();
"<a title="Special:Block" href="/wiki/Special:Block">Special:Block</a> test"
mw.message( 'test2', '[[Special:Block]]' ).parse();
"[[Speical:Block]] test"

The second output should match the first; the message parameters shouldn't be passed as plain text.