I found an article
at icv2.com that sheds some light on DC's distribution methods (as of 2001, a year and some months after Millennium Edition: MAD
#1 was published). It pins down some facts that surprise me:
* In 2001, Diamond was picking up DC comics every Friday. Those issues were being delivered to retailers on a Wednesday, twelve (12) days later!
* Also in 2001, comics meant for the newsstand market were being held by DC for a week and a half. Newsstand distributors were allowed to pick up comics each Tuesday, eleven days after Diamond picked up direct-sales copies, and one day before those issues went on sale at direct-sales retailers.
Under these circumstances, it seems likely that the errors in Millennium Edition: MAD
#1 could have been discovered before any newsstand copies had entered distribution, and that all newsstand copies may have been pulped.
Except for the possibility of a de minimis
quantity of "souvenir" copies claimed by DC employees (or even, perhaps, the printer's employees), I think it's extremely unlikely that any erroneous newsstand versions of this issue could have survived.
By the way, it turns out that icv2.com is a wonderful resource for information about newsstand distribution vs. direct distribution. A search on "newsstand" returns summaries of and links to 178 news articles on the topic from early 2001 to the present. One example: This
article reveals the existence of a newsstand-only Marvel title of which I was previously unaware (unless I missed it in a search, it appears that the CCL Library is similarly unaware of it).