It is possible to Copy an Existing eGC1. However, if it is a Grant Runner application, only the standard part of an eGC1 is copied, not the Grant Runner forms. Details about what will be copied are given on the page which displays when you start the copy process, and in the linked article above.
To copy an eGC1, click the Copy icon in the top right corner of your eGC1 window. After you review the instructional information, click Confirm Copy.