Somebody has to scan this artwork for future generations. AFAIK it's all simply printed and thus fake.....although I really couldn't tell by any of the pics I have seen so far...
I seem to recall an interview with Shigeru Miyamoto that they came across that paneling somewhere and thought it would be great for the game's theme.
I'll see if I can't dig that back up.
EDIT:
Miyamoto:When we made Sheriff, I drew pixel images with another designer and we started searching for materials for the machine’s housing. We would talk about wanting to make a new unit that was like no other one in the world. So we even went to a company that did the interior of airplanes.
Iwata:The interior of airplanes?
Miyamoto:This company could make wood grain prints that looked like natural wood. So we bought these stickers and attached them to the cabinet and made it look like an old American saloon. At any rate, back then, I was doing all of the design from the content of the game to the housing.
From: http://www.nintendo.co.za/NOE/en_ZA/news/iwata/iwata_asks_punch-out_16793_17189.html
