While it may be true, I have never heard of the valve seats coming out of the early G3 Hemi heads because of weak valve springs. I have seen it blamed on overheating.

I hope that is true because my 2007 Magnum R/T has 173,000 miles. If it ever overheats I will probably be rebuilding it soon after.

Were the valve seats all intact on your engine? If so this may be a different problem. However if it is I would say it is not wide spread.