No? I think you're mixing up the fact that they were supposed to release this almost half a decade ago and so random blogs conjectured that it was lost.
I seem to recall hearing or reading that Apple apparently lost the original GM source code for core Lisa software, because the backup tapes were corrupted or unreadable; fortunately a contractor had taken home and retained a profile drive with an alpha version of the source code, but the final/GM version was lost to the sands of time.
(As always, backups are only good if you can actually read them and restore from them.)
However, if the CHM source code is in fact 3.1 GM (as it seems like it might be?) perhaps this story is inaccurate, or perhaps it was recovered somehow. It would be interesting to see if the source code is complete and an entire working Lisa environment could be built from it.
It would be interesting to hear from someone with firsthand knowledge.
