Short answer if you want an associative drawing is No!
If you only want the drawings in Creo 5, export the drawing sheets as DXF or IGES and import them into Creo5.
If you are not planning on making changes to the files, hold them until you do upgrade to Creo 6 or higher.
Install 1 seat of Creo6 for doing any work on these files. If using a PDM system, Windchill, you may have additional issues with version compatibility.