I am aware of the different sizes of the regulator housing, and it's a lazy move from Huma to just copy and paste their info from the Impact, which also makes it incorrect.
The Crown got the larger regulator housing and 10 mm belleville washers on serial number 180760 and after.
These larger regulators are better and are not as much in need of a replacement as the smaller ones are.
Also, as far as I know, the Crowns never had the 14mm reg piston from factory.