KTM 350 weight?

I've heard people talk about Alessi's KTM 350 having a weight advantage over the 450's, however I read somewhere that bikes entering the 450 class can't weigh less than 220lbs. Assuming that is true, it means there is no weight advantage to Alessi's KTM 350. Matthes, is it true bikes in the 450 class can't weigh more than 220lbs?

So if Alessi's bike is the same weight as the 450's, why give up 100cc's? I know this subject's been covered a lot, but Alessi got pulled pretty good last week.