1970 c20 hitch class 1,2 or 3?

[paulbrgr9999]

Trying to figure out what class my hitch is on my c20. The receiver is integrated into the bumper which is bolted to the frame at 4 points on top of the frame rail and below the frame rail. Looks really stong and robust to me but no where on the receiver does it say what the rating is. I cant post pics from under the truck right now, but i included a pic of the receiver bumper. Can anyone chime in here with how I might know for sure what its rated to? I want to pull a small toy hauler total weight loaded will be a few hundred pounds short of 5000lbs.

thanks,

paul