Is there a benefit to minifying JavaScript before gzipping it?

As for raw file size, here is a sample (jQuery 1.4.2):

$ curl http://code.jquery.com/jquery-1.4.2.js | gzip > jquery.gz
$ curl http://code.jquery.com/jquery-1.4.2.min.js | gzip > jquery-min.gz

$ ls -la jquery*
-rw-r--r--  1 me  staff  24545 Apr  7 12:02 jquery-min.gz
-rw-r--r--  1 me  staff  45978 Apr  7 12:02 jquery.gz

So the minified version is about half the size.