I started with a pristine dwg (new with no template), inserted (exploded) the the original dxf file, and then nuked the superfluous stuff like paperspace, layers etc.
Should be noted that this technique will change entity handles. I saw nothing in the dxf file that suggested this would be a problem, but on drawings that are handle dependent (e.g. AutoPlant, Architectural desktop yada) it can have disastrous impacts upon linked intel.
To clarify though, no, I did not modify the original dxf file.