Ladka! I researched and found out that you may be able to give an attestion (see below) about the 'lost' GC at the time of interview. You may not need the replacement GC for that. In any case, it is not a good idea to be without a valid GC for any prolonged period of time - just in case you have to travel or provide it as proof of valid residency in the US.
See below for attestation/affidavit for 'lost' GC >>
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Affidavits or Attestation of Lost or Stolen Alien Registration Cards
Affidavits of lost or stolen Alien Registration Cards will no longer be prepared either at the naturalization interview or at the ceremony for those individuals who do not produce the cards. Attestations will be required. Below is a sample Attestation of Lost Alien Registration Card that should be used for those applicants who have lost their ARC prior to the naturalization ceremony. This form can be provided to the applicant either prior to the ceremony by attaching it to form N-445, Notice of Oath Ceremony at the time of mailing, or when the applicant appears for the oath ceremony. HQBEN POC: Sue Arroyo, Senior Adjudication Officer at (202) 514-8247.
ATTESTATION OF LOST ALIEN REGISTRATION CARD
I_____________________ state under penalty of perjury that I have lost my alien registration receipt card (the Green Card) on or about __________________________ under the following conditions:
I understand that it is against the regulation of the United States Government (8 CFR 338.3) to possess both an alien registration receipt card and a Certificate of Naturalization. I also understand that should I find my alien registration receipt card, I must immediately surrender it to the nearest Immigration Office.
Signature
Date
A Number
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