I see your point its a good question , perhaps with the shorter chassis on the 352 that the extra weight is made from the second spare tire and heavier duel spare tire carrier?
on the other hand when you look at the figures for a chassis and cab only the 352 with or with out winch out weights the 353 w/w 9,167 to 8,800 wo/w 8,462 to 8,100 ??? thats for a1-a2-b1-b2 . Guess we will have to wait for some one to post a pic of their data plate and see what that shows??