ok, the best candidate for the latest material- that being the base dem and the mountains is the project 270912_New_Mountains_Extents_17_*.gmp. 4 of them numbered A1, A2, B1, B2.
The 3rd terrain layer is the lowlands layer which fills in all of the content not covered by the the other two. It is only added to the terrain in the tmd. Do a search for:
Lowlands_x00_y00.png
You can find all of the tiles in a format useful to GM in the folder 40klowlandtiles.
There are 4 of them. This will give you the latest ones at the end of 2012....so looks like the end of 2012...early 2013 was the last outing of the project.
They are in the folder 301012 which agrees with the date of the gmp above and with the Outerra build file in the following post below. So I've narrowed the final run down to between Sep and the Dec of 2012.
MakeRoomforShadowBuild\HILLS_MASK\40KLowlandTiles\301012
I need to check the heights on the base dem with the heights in the "lops" to determine whether the base dem represents the final for output version from the project. The 'lops' were used to level off to a flat plane at fixed heights, the mountains areas. There are two ways to apply the lops. Either within the project itself or at export. Basically, if they are checked in the Control Centre they will be applied to the exported terrain.
Forget the other projects for now.
There is a txt file called "How_to_rectify_an_image"...which gives you the instructions on how to get data of all kinds into the GM project...and also contains some info using Wintopo.
The last project files are in kinda early 2013 I think. But the terrain in the GM project is extremely unlikely to have changed in that last year.
monks