I was in a similar situation about two years ago. I had a two post lift with no tags and no documentation. I did eventually figure out who made it, but in the process found like a lot of things from China, There are 40 nearly identical products by 40 different companies with only slight variations. That said, they all tend to be pretty much the same. Those things are so simple, you really don't need documentation once you understand how they work. The only thing I really needed to find from documentation was the spec for the shielded lag bolts (3/4 x 4" torqued to 130ftlb) holding the thing to the floor. The hydraulics are common (SAE10 aw32 oil), and the shims to get the columns plum are available on Amazon.
The thing the documentation didn't specify, which I added, was concrete anchor epoxy when installing the lag bolts.