Hi Marco, yes you're right. There are also these properties on an object you can access on an object for distinguishing that:

obj.isBRepSubObject - true if object is a sub-object inside a brep.
obj.isCurve - true if it's either a standalone curve or an edge curve.
obj.isEdgeCurve - true if it's an edge curve.
obj.isLaminaEdgeCurve - true if it's a "naked" edge curve that isn't joined to another.
obj.isJoinedEdgeCurve - true if it's not a naked edge.
obj.isSeamEdgeCurve - true if it's a joined edge but its the seam of a closed surface so it's the same face on either side of it.
obj.isStandaloneCurve - true if it is a standalone curve and not an edge curve.
obj.isCurveSegment
obj.isEdgeCurveSegment
obj.isBRep
obj.isSolidBRep
obj.isOpenBRep
obj.isSingleFaceBRep
obj.isFace
obj.isConstructionLine
obj.isPointObject
obj.isMeshObject
obj.isTopLevelObject

- Michael