Longhorn Late M4?

[Windows2005]

What happened between Longhorn 4011 and 4015?

First off: Here is a potential build list of Longhorn builds that could have been compiled at the time (based off file versions) Which I found while looking though builds like 4015 and some build lists.
4010.main.030221-2133
4011.main.030305-2045 (Leaked)
4012.Lab06_N.
4012
4013.Lab01_N.030318-1738
4013.NT.030320-1058
4014.NT.030324-1840
4014.Lab01_N.030325-2000
4014.Lab01_N.030326-2000
4015.main.030328-1500

Now we know sometime in between 4008 and 4015 was DWM added, Plex was updated, Milestone 5 Background, Winver was changed back to 2003, The new login screen was added, Prototype Help Center, and some other features

But really? What builds would you expect out of the list to be leaked/revealed or which one would seem the most real? Interestingly from where I see it, 4013 could have been the first Server build (aka Server 2008)
Or do you have any information/potential builds that may come in soon?
(I think one of the 4014.Lab01_N's is a typo)
and for me, I feel like 4012 could be real!
and also, they could all be fake I know

[anonymous74]

DWM has been in longhorn since 3683, it was just called DCE (desktop composition engine) instead. 3683's DCE only works on real hardware though. I've gotten it running in a 4011 VM. Also, the updated Plex taskbar was able to be enabled since M3 builds.

[Windows2005]

DWM has been in longhorn since 3683, it was just called DCE (desktop composition engine) instead. 3683's DCE only works on real hardware though. I've gotten it running in a 4011 VM. Also, the updated Plex taskbar was enabled since M3 builds.

Yeah the updated taskbar was introduced back then but it only was rolled out permanently onto the Plex theme
DWM got the transparent frames in 4015 and I thought that maybe an earlier compile would include the earlier theme

also, I want to note I found a 2nd 4018 file version from 4020 (6.0.4018.LabXX_N.030421 and is mislabeled as .30421) And will continue to find build numbers from file versions

[Evo]

(I think one of the 4014.Lab01_N's is a typo)

I don't think it's a typo. If you look at the Source Code of Windows XP, then Lab01_N is mentioned there, so...