Standard Spec Swingweight is around D2?? Mizuno have B heads which are lighter so that over length shafts can be installed and a circa D2 Swingweight achieved , unless you require different.
You can weigh each iron in grams or Oz and then from the balance point measure the length to the grip end /cap in inches and deduct 14 inches and then multiply this figure by the weight.
There is a comparisons table available to see what the swing weight is.
https://www.tutelman.com/golf/design/swingwt4.php
Mizuno and Ping two of the manufacturers that are really on the money with tolerances, doubt your irons will be C9 unless you ordered the that way