SpecialNewProperty and SpecialNewItem directly entities from form data and do their own validation inside validateFormData.
New store fingure print uniqueness validation was introduced as a validator executed inside ChangeOpFingerprintResult, so since the aforementioned two specials do not use ChangeOp to create the entities (unlike the other specials such as SpecialSetAliases .. etc), they will have to be updated to use the new store conflict detection directly as well.