I have the following plugin's installed.
MB User Meta, Meta Box, Meta Box Builder, Meta Box Columns, Meta Box Include Exclude, and Meta Box Updater.
Now, when I click on the the Meta Boxes and then click on "All Meta Boxes" It will show all the published meta boxes.
I hover over the one I created until Duplicate shows up, which then I press. It will only open a "Add New" window, without any of the original information.
Does that help?