I am looking at an 18 ft enclosed trailer and it is a '94. It looks similar to newer ones but has ribbed or corrugated sides. Are the older ones a lot heavier than the new ones, for some reason it just looks heavy. It is a united express or something like that. It seems to be a good trailer just a little ugly with the corrugated sheeting, but i am mostly concerned with it being a lot heavier or something different that they have changed or updated on the newer models.