Within the native Creo model you can specify a 3D dimension as a so-called inspection dimension or a basic dimension. This property can be interrogated in Creo Toolkit with the use of the API ProDimensionIsInspection and ProDimensionIsBasic. There is also a parameter PTC_DISPLAY_TYPE when interrogating the 3D dimension manually that can hold the values "Basic", "Inspection", "Neither".
When you export this model according to STEP AP242 the property "Inspection" is lost in the translation. After importing the STEP AP242 file there is also a parameter with the name PTC_DISPLAY_TYPE which can hold the values "Basic" or "Neither". It seems logical to me to use this parameter to also hold the value "Inspection" as is the case in the native model.