Is this it? Doesn't really show them making the shell, just removing the pieces from the mold.
Their next lightest campers are the Sportsman models that weigh 2360 lbs dry. I'm skeptical that the 610 ever weighed 700 lbs. It's hard to make a viable shell that light... and then add finishing, furniture, cabinets, cushions, stove, fridge, toilet, tanks, propane, plumbing, electrical, batteries, vents, windows, door, etc. Yes, I know the old 610 was small, but still...
I was going to mention something like this.
You can be sceptical but many of us, me included owned one and weighted them. Mine was under 700lbs empty and 900lbs loaded. So…those weight are real.
You mention good point, dimension will be different. That should not influence the weight much tho.
northern-lite.com
It won’t be tough, It is impossible. My event experience was with new Hallmark Guanella and the Ford F150 that everyone said would be fine. The trucks payload sticker said 2575. I took off the tailgate and 2/3 of the back seat. Everyone was impressed when it was loaded but when I got home 5 weeks later and unloaded all the food and clothing, and with only a half tank of gas, no passenger , no dog and very little propane, I weighed 8300. Add gas, my wife, my dog food and clothes and I suspect that I was traveling at 800 to 900 pounds over the trucks 7850 gross.
Their "claim" is regarding the 1st part, not the 2nd. Your payload sticker isn't their concern... or even yours unless you want it to be.
It's true even of small and light campers, that may weigh <1000 lbs when empty and dry, but once you add all your stuff and doodads and upgrades and armor, and load it for extended camping, you now have added >3,000 lbs on your truck and are 1,500-2,000 lbs over GVWR. There is a good article on here somewhere about an Alterra camper on a Tacoma.