Should installation process fix firefox, thunderbird mailto problem?

["Edward C. Jones" <edcjones@comcast.net>]

After I install the firefox and mozilla-thunderbird package, mailto 
links in firefox and http links in thunderbird do not work. The 
well-known fix is

In the "prefs.js" file for firefox put the line:

user_pref("network.protocol-handler.app.http", "mozilla-firefox");

and in the "prefs.js" file for thunderbird add the line:

user_pref("network.protocol-handler.app.http", "mozilla-firefox");

Should (Can) this be done automatically by the installer for the packages?