The Nylex poly water jerrys have been around a long time.
I have some dated 1997 and the same jerrys were around long before that. I have a photo of the same design (maybe different maker) being used by 1ATF in Sth Vietnam.
The 1997 ones are marked with a broad arrow and the year and a NSN. They have "V.B. Plastics" and "Australian Made" on the base. They also have NSNs on the jerry cap retainers (the bent bits that keep the caps hanging on the jerry after you unscrew the cap).
I recently brought a new water jerry at Roof Rack City: its the same colour and shape and size --either they use the same moulding machinery from 20 years ago or its a good copy - the design hasn't changed it just the markings details which are a little different. The broadarrow is fake looking compared to the original ones and the jerry NSN is different in the last 4 digits, and the NSN moulding inlet is longer. The cap retainers are not marked with an NSN. The jerry is still marked "V.B. Plastics" and "Australian Made" on the base.