Hi, Alex. Wurger is correct. Also, to maintain the laminar flow effect over the wing, the first part of the mainplane, I believe up to the main spar, was coated in a special 'putty'-like substance, which was buffed and polished. The 'aluminium' finish, which was a laquer-type coating, was then applied and this, in turn, was highly polished. Close examination of period photographs, particularly colour close-up shots, show the distinction in 'texture' quite clearly. I have an article published in a modelling magazine from the '70's, that describes the finish, including the colours (and their construction) used for the interior, and particularly the wheel bays, an area that many modellers STILL get wrong! If you are not in a mad rush, I'll dig it out but, I don't think the text will show up very well on a post, as the pages of the mag are getting old (like me!), so, if it's of interest, I might have to copy it and mail it to you. Hope this is useful.
Terry.