strange plates, not dog-tags, but what ?

[just]

Hello
have you seen that before ?
I think it's military, but which country ? may be US or british ?
thanks for answers
cordially
Didier

[Trackhead M2]

Hello
have you seen that before ?
I think it's military, but which country ? may be US or british ?
thanks for answers
cordially
Didier

Dear j,
I've never seen this type of tag. The shape suggests it's American. The CO abbreviation also suggests American as the British abbreviate Company as COY or CY while the US is CO. Maybe, it's some sort of equiptment tag.
Strike Swiftly,
TH-M2

[just]

Hello Gentleman
thank you
cordially
Didier