These likely came from a return pallet, and have no original packaging.  It looks like someone tried mounting them and then returned them.

My research indicates a GMC or Chevy, but please verify measurements.  

This is why I am selling them so cheap.  I am not a mechanic, so if you are doing the work you have more knowledge than me on these parts.

If you want any additional measurements, please message me and I will be happy to provide.