Early/mid Vietnam collapsible canteen bladders, period marking?

[Username]

Recently acquired this small lot of Vietnam era items, first aid kit is post Vietnam. Collapsible canteen is in nice shape, and even came with a spare bladder. The cover is marked on the back to "Schwerdt GNS". Not sure if the marking is period or not. Any info would be appreciated.

[Username]

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[falcon_ib]

I'm not used to seeing white markings on VN items - would love to see what forum members find

 

Evan

[Ronnie]

That's probably the guys last name and initials. It is not factory for sure.

Ronnie