WW II Army Air Corps Discs ??

[unit91]

Are these from WW II ?  Note that the backs are different.

[atb]

Yes. Both could be from WW2. The one on the left with the screwback fastener takes a round screw-on thumbnut, not that clutchback pin fastener shown with it. The stamped design on the right replaced the multi-piece screwback style as the issue EM collar disk in around 1943.

[unit91]

Thank you!