This is not correct for several reasons, the most blatant of which are:
#1 there are MANY off shore forging business and only a few USA/Canada based factories. The differences in them are HUGE.
#2 the company that purchases the casting dictates the casting tolerances and the metal mix that is used in the casting, the tighter the tolerances and better the metal the higher the initial cost.
Even if a Dart and Pro Comp head came out of the same place it IS NOT the same part!