FAA Shoulder Boards and Cuff Insignia

[FAA_REG]

Hi, guys, a newbie question.

I've just started researching Fleet Air Arm uniforms from WWII.

I have noted that many of the shoulder boards and sleeve/cuff insignia have a 'squared' circle rather than the rounded style seen on RN uniforms. Am I confusing this with Volunteer Reserve type designation or was there generally a difference for the FAA.

Thanks in advance for your help

REG