Don't worry about it. Using NURB's to generate basic starting shapes is probably the most common use for NURB's in Maya, but has really nothing to do with NURBs surface modeling.

If you want to learn the basics of hard surface polygon modeling the Mech tutorial by Kurt Boutilier is a fine tutorial, as are the apache series, the spitfire, the land speeder, the tie fighter, and the jedi fighter. But these are ALL polygon modeling tutorials and have very little to do with NURBs aside from generating basic starting shapes.

Anything by Kurt Boutilier will generally start with NURBs just to rough out the basic mass of the model and then will be converted to polygons from which the remainder of the model will be built. That is just his style of modeling which is generally a good approach for organic modeling but Kurt has managed to make it work quite well for inorganics as well.

Hope that clears things up for you and if you decide to try out one of the tutorials I am sure you will find some useful techniques along the way and hope to see some WIPs in the forums.

Cheers
-Rick