No, your .EFT File doesn't expire and you can use it for multiple tax stamp applications. Although, your .EFT File doesn't it expire, you may want to get a new .EFT File if the contents within the .EFT File changes, e.g. your name, address, significant changes to your weight, hair color, etc.
Applying with the ATF's eForm site can be easier when you have an .EFT File for your fingerprints. However, some of your responsible persons may not have an .EFT File. Can you upload an .EFT File ...
If you are an alien, you will need to enter in your I-94 Number, USCIS Number or AR Number. You can add your USCIS Number or "A" Number into your ATF eForm application on the Applicant page under ...
This information is from the ATF website following the new rule for July 13.
FINAL Rule 41F – Background Checks for Responsible Persons – Effective July 13 2016
On January 4, 2016, the Attorney ...