This is actually pretty interesting...
I have the 3 maps in screen shots. Here are the links as they are large.
http://img.photobucket.com/albums/v202/JossiRossi/CTCE/ctow000.jpghttp://img.photobucket.com/albums/v202/JossiRossi/CTCE/ctow007.jpghttp://img.photobucket.com/albums/v202/JossiRossi/CTCE/ctow002.jpgNow, since the 1999 is only partial (and even though it's pretty clear looking at them) I've overlaid the 1999 map onto the Present map. As you can see they line up (without alteration actually). The important stuff is the Eastern Coast of Truce where the beaches line up nearly identical.

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http://img.photobucket.com/albums/v202/JossiRossi/CTCE/Present1999.jpgOk so we know that 1999 AD, lines up with the Present. Therefore if something lines up with the present then it lines up with 1999. So the big question is, does the future line up with the present in the same way? It does.

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http://img.photobucket.com/albums/v202/JossiRossi/CTCE/PresentFuture.jpgThere's a lot of changes to the map (however there are also some drastic changes between 600 AD to the present, and thats without the extra years or the presumably destructive changes Lavos may have made but that's interpretation.
The one thing that is clear is that the Sun palace is in the same place. If you missed the HUGE red circle then I'm not sure I can help you =]
So through the transitive property =] (If A=B and B=C then A=C) applied to the coordinates of each map. Then when I place 1999 AD onto the Future map, then those are the exact correlary places.
Placing the 1999 map over the Future map gives us this.

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http://img.photobucket.com/albums/v202/JossiRossi/CTCE/1999Future.jpgNow refrencing this picture I posted before.

Lavos breaks out of the ground definitly above Death Peak, by like maybe 7-10 tiles. This is not perfect. Not nearly definitive enough, although the fact it is also on the same vertical axis almost, if not perfectly, is promising.
So there is the distinct possibility. However, given the undeniable information (I personally think. I think I did a good job with keeping all my stuff unbiased) the ultimate conclusion is up for grabs. However, this is all the info we have and ever will have for certain. All other pieces of information can be up to interpretation or debated, the above info is likely the only true fact that can exist in this discussion. In the end it depends on what the person is willing to believe. If you look at this data and see a mountain made from lavos then that is what you will likely always see. If you don't see that and just see it as a regular mountain (albeit one that people think is freaky) then that is also what you will likely always see.
Now, as for my opinion. I think it is Lavos. The mountain is a different shape, it's linked to Lavos somehow, has plenty of lavos spawn which isn't too common elsewhere, as well as other debateable correlative evidence.
And I'm spent.