Can you please share the details of your requirement regarding dynamic block. Perhaps, a sample file with snapshot will be helpful in understanding that.
Dynamic Block is just a feature of AutoCAD UI - it is converted into CadInsertObject internally. So there is no difference from prospective of Aspose.CAD API and internal structure of DXF/DWG. Dynamic blocks are just variations of CadInsertObject with specific properties set. Please refer to following API reference link for your convenience.