WWI M1916 holster - unit identification

[Tomasz70]

Hi there, I have tried to identify the unit that this holster belonged to. Unfortunately, nothing reasonable came to my mind.
Does anybody recognize those markings? 
First row: F.28.78
Next row: 5.A.T.
Holster made by BOYT in 1917.

Thanks for your assistance!

T.

[atb]

"5. A. T." is possibly 5th Ammunition Train. "F. 28. 78." May be a sub unit (F 28) of the Ammo Train and the soldier's equipment accountability number (78).

[Tomasz70]

Thanks a lot! That sounds quite properly. Then, this unit saw some action in 1918 within the structures of the 5th Division. Really nice information!

T 

[atb]

That F.28.78. could also be another unit to which the holster belonged. I would think a former unit's marking would have been marked out, though.

[kfields]

2 hours ago, atb said:

"5. A. T." is possibly 5th Ammunition Train. "F. 28. 78." May be a sub unit (F 28) of the Ammo Train and the soldier's equipment accountability number (78).

I like where 'atb' is going with this and agree with 99.999% of what he said. Also looks like the 28 over stamped something else and maybe the 78 is part of that prior marking? So maybe it was Company F and the 28 is the soldiers ID?