Help With Corporal Chevrons

[militbuff]

Does anyone know if these corporal chevrons are WWI era US Army chevrons or are they police chevrons?  If army, what branch?  Much appreciated!

 

 

[QED4]

Could be for the AAF Dress Blue uniform from the 1920s-30s. The background material appear to be black though and they do have a police look to them so really hard to tell.

[CAC1901]

Looks like Prussian blue on black with orange or faded red chain piping?  I've seen a number of color variants to this pattern - typically some shade of blue with chain piping - with attribution to the British Army, police, or a band.  The one confounding picture in Emersons book (for me) is the general pre-1920 corporal which illustrates a similar white piped blue chevron with no explanation and no correlation to a pre-1920 US Army regulation.  

[militbuff]

Thanks to both of you for your thoughts.  I was thinking they might be the post WWI AAF dress chevrons.  They are prussian blue on orange with chain piping.  I just can’t find any examples anywhere in Emerson’s book or online.