Pathcode copy probably will not work between releases, but you can try - it was discussed here some years ago, along with a few other manual cheats, I believe.
I guess, if Boomerang was free you wouldn't object to using it, especially considering that it uses JDE API's to do all manipulations and not direct DB access.
If you are determined to do this manually, running the Upgrade Workbench for a small set of Objects may actually be the fastest and the most reliable way. You already have the two systems in place, so this can be done in just a few hours. To compare, copying specs across, if works, may take as long or longer...