My 1982 weighed in @ 435#at the 2001 Nationals, My 1988 weighed in @ 411# at the 2003 Nationals
If your only concern is with the weight of the boat as you are moving it around on the beach, take the Daggerboards off when you are moving it, and there's your difference.
At the Clear Lake nationals, the Heaviest Hobie 18 in the event was one that had been badly damaged and poorly repaired, it weighed about 465# and his two best finishes were in the lightest air races. If you let the actual weight of the boat get into your head, you are only messing with yourself. I lose way more in one bad tack than I ever give up because of a boat that is a few pounds heavy.
As Matt said, quit worrying about it and enjoy sailing the boat.
Stephen