I was thinking of posting this and Alaska Jim's post encouraged me to do so.
It is on my 53 GMC 3 ton grain truck. I personally find it unusual, as I am use to these old grain trucks having unbranded, under-box hoists. Normally I see this behind cab type on dump trucks.
I did try it and it does work, though the cylinder did leak when it got near the top. Also, should the leaver have a neutral position or do I need to disengage the PTO for that?(hence why the leaver is in the cab.)