There is no way that the hoist was installed by GM. Hoists were always a locally installed item.
You've got to be careful with the hoist on a pickup body. The box was designed to be supported by the standard mounts to the frame and doesn't have the strength to withstand dumping heavy loads over a period of time.
There are still people attempting to sell these hoists, but my experience has been that they all tend to break up the body over a relatively short period of time.
If you're going to use it as a cool looking unit for shows, you'll be just fine, but with heavy loads, trouble will find you.
