Are the older campers a whole lot lighter than newer ones?

Our '78 TC with full propane and water weighs in at 1200 lbs - according to the manufacturer. I haven't scaled it. I'll make note it does not have any waste tanks and I'm sure there is a bit of difference with those on, especially full. We have a thermal cooler in it which weighs about the same as the ice box it had originally and not a refrigerator like a new one would have.