Dealer or manufacturer? I used to have a Fontaine, 1996 model, and I emailed Fontaine a couple years ago and they emailed me back the ratings of the stake pockets, chain spools, etc. The dealer likely doesn't have a clue but the manufacturer should know.
Call the manufacturer. I’ve gotten new vin plates and securement rating stickers for several brands. Some are free (!) most are not. Some require a cert from a dealer proving ownership.
Say you're securing a bulldozer, and you run a chain from each side of the trailer to the drawbar pin on the dozer. Is that considered a single point of attachment? The drawbar and the pin have a crazy high weight rating, more than equal to the drawbar pull of the machine.