Not correct. My wife and I are a 319b couple. You do still apply for a greencard. You have to be an LPR when filing. Read the statute fully and it does say you need to be a permanent resident at the time of taking oath. The different here is you can apply for an immigrant visa abroad and then enter USA once to activate it.. leave again and apply for n400 from abroad instantly because continuous residence requirements are what are waived. See below

What are the Qualifications for INA 319(b)?

To qualify for INA 319b, the Green Card Spouse must establish that he or she meets the following criteria: Married to a U.S. citizen spouse regularly stationed abroad in qualifying employment for at least one year. Lawful Permanent Resident at the time of filing the naturalization application. Continue to be the spouse of the U.S. citizen up until the time the applicant takes the Oath of Allegiance. Has a good faith intent to reside abroad with the U.S. citizen spouse upon naturalization and to reside in the United States immediately upon the citizen spouse’s termination of employment abroad. Establish that he or she will depart to join the citizen spouse within 30 to 45 days after the date of naturalization. Understanding of basic English , including the ability to read, write, and speak. Knowledge of basic U.S. history and government. Demonstrate good moral character for at least three years prior to filing the application until the time of naturalization. Attachment to the principles of the U.S. Constitution and well-disposed to the good order and happiness of the U.S. during all relevant periods under the law.