Can't find KDZ for LG E970 AT&T

I'm stuck at recovering my phone from "Security Error". I tried LGNPST but it didn't work. Then I tried KDZ updater, but I'm again stuck :( I don't know phone's IMEI and I can't find its KDZ files anywhere. Can I use KDZ files of E975 instead ? Help plz, I'm beginner :(