I have a copy of the fitting instuctions, if you want Frank? It is a Word Doc, but I don't know how to post it on the forum.
I would like the contact details of the guy who has them, if you can too.
If they are a Jeep box, then it is just a saginaw, at least you know it is strong enough to turn heavy wheels/tyres and put up with the rigors of 4x4ing. Over here, when we use HQ-WB boxes in RHD Jeeps, as they are Saginaws too, so I would guess they are pretty generic.