Could you please set the value of the code field on the claim award page to $_REQUEST['code'] instead of $_POST['code']? This would allow admins to simply provide a link to the claim award page with the code already in the field, rather than telling them to manually copy the code and find the page, etc.
As a step further, it might be cool to allow us to actually submit a code via the URL, so that the code can remain secret (important for rarer/harder to get awards). If a person never sees the code, they can't potentially pass it on to undeserving others. Of course, this would require that the query string be emptied immediately so that the code isn't simply left in the URL anyway.
But if the second part is undesired, I hope that we can at least have the first.