Yes, starting with UCCX 11.0, it is possible to import duplicate records.
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cust_contact/contact_center/crs/express_11_0/release/docs/UCCX_BK_R7697E6E_00_release-notes-for-uccx-solution/UCCX_BK_R7697E6E_00_release-notes-for-uccx-solution_chapter_01.html#UCCX_CN_O1093603_00