Do all Argos have chain tensioners?

[Iamnotabot]

I have a 1970's Argo 6x6, it's got the original 2 cylinder 2 stroke Kohler.

There are no chain tensioners, nor any mount holes or witness marks where tensioners might have been mounted.

I'm probably going to make some, or Rob ones out of one of my Attex parts rigs.