How can we differntiate whether the assignments are created by adhoc flow processing or by the flows used in case type rule?
Is there any property/parameter present on pxFlow of work object or on Assignment page to differentiate that the flow/assignment is created from flow rule that is part of a case type rule or through adhoc flows (adhoc flows can be optional processes or created manually using OOTB activities like startNewFlow or created through link with option to start a flow)
I am not aware of a property to differentiate that. But I'm curious why it matters. What is the business problem you are trying to solve? It seems like you can use other aspects of pxFlow to know if the item's call stack was a specific case type that you care about (or not, as the case may be). Failing that, you could probably create a property to track the association to/disassociation from a specific case type.
I suggest you create one of each, and for each, you right-click on the assign-page in the clipboard viewer, choose "copy xml of page", then save it away, and compare the two results. See if there are any usable differences revealed.