You mean you want to export to a P2 MXF from a P2 MXF sequence, that has already been rendered as DVCPROHD MXF, correct? I'm guessing that, so long as you check the "Use Rendered Previews" box in the export settings, Premiere will more-or-less do a copy operation of your rendered MXFs into the new destination MXFs, though the files will be split into 4GB chunks per the P2 specifications.
You can try to export a short bit of your sequence with these settings, import that video, and lay it on top of your original; set its transfer mode to Difference and toggle over to Y/C Waveform view in your Program Monitor. So long as you see nothing but a solid line at 0 IRE with no "fuzz," you can be assured that no reprocessing of the frames took place (though the export speed will be a good, though less scientific, indicator of that as well).
Thanks a bunch. That is exactly the answer I was looking for. Your the man.
Did the tests and it rerenders for sure.
It re-renders for sure.
Would be a good feature request though. It would be pretty cool to be able choose your pre-render format and possibly use the file as your delivery format.
Thanks again Colin.