Hi @Luis_Pacheco_3D. I'm pretty sure that parts have had the ability to include and use custom view representations for well over a decade, because I have been using them almost as far back as I can remember. They are just not as prominent, or as commonly utilized at the part level as they are at the assembly level. However, positional representations are unique to assemblies. And back before ModelStates, the LODs (level of detail representations) were also unique to assemblies, but in 2022 they introduced ModelStates to both parts and assemblies, because although the old LODs primary purpose was recording suppression status, the newer ModelStates record much, much more now, including parameter values, property values, feature suppression, which assembly components are set to which ModelStates within an assembly, and more. When I go back into the 2023 online API help, I can find the PartComponentDefinition.RepresentationsManager property there, and it says that it was introduced in version 2012. From there we can bet to the RepresentationsManager.ActiveDesignViewRepresentation and RepresentationsManager.DesignViewRepresentations properties (both introduced in version 11). Then the DesignViewRepresentation API object's help page also says it was introduced in version 11, which according to Wikipedia, came out in 2006. iLogic itself only became available in the 2011 version, I think.
Manually, in the part's model tree, we don't see a folder named 'Representations', like we do in assemblies. In assemblies we would have to expand the browser node for that Representations folder to see the view representations browser node, and the positional representations browser node.

But in parts just see a structural/tree type symbol with the word "View" next to it, followed by a colon ":", then the name of the 'active' view representation.

When we expand that browser node, we can then see the built-in, locked view representation that is present in every model document named "[Primary]", and used to be named "Master" in versions prior to 2022. If we then right-click on the main views browser node, then choose 'New' from the context menu, we can create a new/custom view representation. I have made a custom view representation directly within all of my part and assembly type templates named either "Default" or "DEFAULT", and made sure it is the active one when saved, that way every new part I create from any of my templates already has that custom view representation in it that will properly record the way I want that model file to look in all assemblies that I may put it into later, when I set the component to that view representation. This small preparation has saved our company an incalculable amount of time and countless headaches over thee years since I implemented it.

Wesley Crihfield

(Not an Autodesk Employee)