IS THE COPY OF AN INSURANCE BENEFICIARY DOCUMENT AS GOOD AS THE ORIGINAL IF THE ISSUE IS TAKEN TO COURT?

MY BROTHER IN LAW SIGNED A BENEFICIARY FORM TO ADD MYSELF TO THE ORDER OF PRECEDENCE IN THE BENEFIT PAYOUT OF HIS INSURANCE WITH FEGLI. THE SIGNATURE WAS WITNESSED BY TWO SEPARATE PARTIES. I SENT THE FORM TO THE OPM AND I CANNOT GET THEM TO TELL ME IF THEY RECEIVED THE CHANGES AS MY POA IS NOT VALID WITH THEM. IS THE COPY I RETAINED SUFFICIENT AS EVIDENCE OF INTENT? THEY REQUIRED THE ORIGINAL SIGNED DOCUMENT.