If you look at this page http://www.hannants.co.uk/search/index.php?&product_type_id=2677&scale_id=955&manufacturer_id=8274 It should give you a fair idea of what is available. The other thing is just to make sure your spit had this kind and colour of code and then your laughing. You should be able to make it up from whats available. If not there are other ways to do it.

Ie getting someone with a waterslide decal printing expertise to make the actual set for you or getting some film and cut a mask out to paint the codes and serial on.