Interesting, I've never tried using bevel/emboss on a height map before; but then GIMP's bevel/emboss features are far more limited than that of PS. In GIMP you can use "Bump Map", a feature which I do not believe PS has (though correct me if I'm wrong), but you can also use "Emboss" to achieve a similar effect. I believe that and "Lighting Effects" are the typical choices for achieving the appearance of a 3D texture in Photoshop. At least that is the impression I got from reading Jezelf's tutorial (it's the last one on the list). You might also want to have a look at a2area's majestic, if somewhat complex Israh tutorial, since the Wilbur and Photoshop settings may be more applicable to the software you are working with than my tutorial will be.
As to the 3D effect you've achieved here, the test will be how well it handles a gradient map, or perhaps the color palette you choose for your gradient map. PS is vastly superior to GIMP on this score (see Jezelf's tutorial), as it offers a preview window that allows you to edit as you go. However one initial concern I have just looking at this image is that I wonder if the mountains have sufficient elevation to really pop out once you've added a gradient map. In my own experience I've found that I need to have quite a bit of contrast in order to make the mountains really pop. But like I said, it remains to be seen. You may discover another way of doing things!