It appears that calling the "HasRights" function within core.js is the right move, but I cannot seem to find a definitive reference on what values I should use to call it with.
In looking through core.js I see an indication that the following is correct once in the context of a particular drop down.
My tests also indicate that it is the right check. However, I would feel a lot better if there were some definition of this somewhere.
Also, does HasRights work for both SharePoint 2007 and SharePoint 2010? I am testing in SharePoint 2010 but need this to work in SharePoint 2007 as well.