The same rules(Modeling Single Parts) also apply to assemblies:
If several individual parts are installed, each with a classified "CNS_CP" (formerly "RVT_CP" [Revit Family Template Mapping point] in the eCATALOG 3Dfindit classification "CNS"), the first component in the assembly structure (which contains the point classified with "CNS_CP") is generally used for the placement of the assembly.
The order of the parts in the assembly structure is generally retained, subject to system optimizations (on-premise ENTERPRISE 3Dfindit installations / PARTcommunity CAD backend).