Booleaning them together would make them share uvs and therefore at least initial textures.
However, some things to consider;
- if your model is not a totally enclosed volume (ie - the centerline split of the dino is not a face or series of faces, but is rather an open hole), then the object is (if I remember correctly) non-manifold geometry, and will not Union along that edge/face. Depending on the situation, it will not boolean at all, even if you close the face or combine it with another shape.
- secondly, if you have initially textured your model, then booleaned it, wierd things 'might' happen to your textures (especially if the have maps assigned). This is largely due to the fact that the program will try and fit all the new connections (and the stuff from both previous objects) into the square - you can end up with several different pieces using the same texture this way (probably not what you want). Most likely you'd have to re-map the mesh (so texture after the entire model is done).
- you might be able to get the object to share a single map if you tell it re-auto map the object, but I haven't tried it (that I remember), so no idea what will happen....