The P3D- is all software.
Evidence in favor of this:
The PNs on all powertrain parts are 100% identical to AWD- both in the parts catalog and on every actual car owners have looked at and posted pictures of.
and
A number of folks who ordered Ps, but were delivered AWD cars, had the AWD software-flashed to a P on the lot.
And
Much above 60-70 mph the P and AWDs actual performance is nearly identical too despite the software differences.... and the dyno curves make it pretty clear the AWD is being software limited below that.
Versus...evidence against:
Literally nothing other than Elon making a vague tweet about binned motors before the first P was ever sold. (which isn't even evidence against if it turns out all motors passed the testing which would make sense given the PN thing- in contrast when Intel or AMD or Nvidia or...anyone... actually bins parts with significant performance differences they give them different part numbers after all)