In the drop-down for "add existing field" not all fields are available for reuse. Specifically I would like to reuse a field of type "list (integer)" because I will be adding 300 of them to my content type with exactly the same settings (just different labels and machine names). Doing the manually is going to take me over eight hours since it takes about 1.5 min to add a field and configure it's settings. Is it possible to reuse fields of type "list (integer)"?
ps: if you are unsure what I mean by reusing a field see here: Documentation for Field-UI and look at the section titled, "Reusing Fields".