Hi AnointedMatt,
Yes … they don’t need to pass the fire regulations or include a tag that says they have.
If you calculate the volume of the topper (in cubic feet) and then multiply it by the density that it’s supposed to be then you would end up with the weight that the topper “should be” (excluding the weight of any cover).
For example a 2" queen size topper that is 60" x 80" would be 60 x 80 x 2 = 9600 cubic inches which divided by 1728 (the number of cubic inches in a cubit foot) = 5.56 cubic feet. If you multiply the cubic feet by the density of 7.5 lbs/ft3 then that would equal 41.7 lbs which “should be” the weight of the topper excluding any packaging or the weight of the cover.
I would keep in mind that the better manufacturers and retailers don’t generally “negotiate” (see post #6 here) or have “fake sales” based on the time of year or holidays (see the guidelines here and post #5 here) and I would treat retailers or manufacturers that negotiate their prices or have “major holiday sales” as a red flag because manufacturers or retailers that sell good quality/value mattresses don’t need to negotiate or have “fake sales” to create a false sense of urgency and sell good quality/value mattresses every day of the year at prices that are already very reasonable.
Phoenix