I'd actually parent the mesh to the locator. Snap the locator to a vertex of interest: select locator, select the move tool, hold v and MMB drag a little bit on the vertex, it should snap as long the move tool is free to move in all three axes(click the yellow box in the middle if not). Then select the mesh, shift select the locator and hit p. Do that for both meshes. Then select the first locator and do the vertex snap on the other locator. Both locators should now be in the same spot. You could do it with constraints, but this is the simplest I think.