Krinkle wrote:
So any page deleted after June 2005 will retain the same low old revision if when restored. However any page deleted before 2005 didn't have the saved revision-id, so when any of those pages are restored now MediaWiki generates a new revision-id, just like it does for Import, just like it did before 2005 for undeletion.
Part of this is wrong. When a page is undeleted, it gets a new page ID, no matter when it was created/restored. While the old page ID is stored in the archive table, it isn't used during undeletion. This is the subject of bug 26123: https://bugzilla.wikimedia.org/show_bug.cgi?id=26123.
I just tested this again on test.wikipedia.org to make sure I wasn't crazy/that the behavior hadn't changed since I last looked. It definitely does not use the old page ID upon restoration. As noted on the bug, one of the potential problems here is that you can have multiple options to choose from.
MZMcBride