DonM His grips are 123 grams, which is why the swing weight is so low. They probably feel like sledge hammers anyway.
520ish grams per club is definitely on the heavy side (my 7-iron - Ping i210 with stock AWT 2.0 regular shaft and midsize grip - is around 425 grams, for example), but most of that additional weight will be in the grip. The shaft being used in the irons will also contribute - doesn't say what shaft is in the irons in the article, but I'd be very surprised if it's not significantly heavier than the mid-90s AWTs.
Another detail that caught my attention was just how upright those clubs are - 66.5° is close to 5 degrees more upright than the standard lie angle of the 37.5" club (6-iron) in the i230s...