Check if Apache is adding Access Control Headers to my font Files (Firefox Cross Domain @font-face problem)

Question

I'm trying to work though the firefox font face cross domain issue. http://stackoverflow.com/questions/2856502/css-font-face-not-working-with-firefox-but-working-with-chrome-and-ie

The solution involves rewriting headers using .htaccess

<FilesMatch "\.(ttf|otf|eot|woff)$">
    <IfModule mod_headers.c>
        Header set Access-Control-Allow-Origin "*"
    </IfModule>
</FilesMatch>

I'm not sure if this rule is being applied - is there a way that I can test for this? I've looked at my font assets in firebug but the server response doesn't indicate that anything is different...

Response Header from font asset in Firbug Net Panel.

HTTP/1.1 304 Not Modified
Date: Sun, 17 Jul 2011 18:57:42 GMT
Server: Apache/2.2.14 (Ubuntu)
Connection: Keep-Alive
Keep-Alive: timeout=15, max=99
Etag: "e7ce-2e78-4a8475f98a336"

Is there an easy way to test if this rule is being applied? I've checked my apache config and the module is loaded.. from phpinfo();

Loaded Modules
core mod_log_config mod_logio prefork http_core mod_so mod_alias mod_auth_basic mod_authn_file mod_authz_default mod_authz_groupfile mod_authz_host mod_authz_user mod_autoindex mod_cgi mod_deflate mod_dir mod_env mod_headers mod_mime mod_negotiation mod_php5 mod_reqtimeout mod_rewrite mod_setenvif mod_status