I'm skeptical about some of those dates, as it would be more than the six issues per year release schedule that TG followed, and I don't believe they ever deviated from that. And I see their website lists some of those issues with another date under the Call Number. For example, their listing for April 2003 also has "Note: 2003 March"; going by this forum archive, there exists issues for March, May and July, but not for April.
That said, I think this does help give a nearly complete run of the magazine, as there were only two issues in 2003 that I weren't sure of, and this seems to confirm there was one final issue in 2005. All that's left is, theoretically, one issue from before October 2001.