Thank you so much for your inquiries. I have sold my three running lamps. FYI: Having just remarried, my husband rewired the five with the following lenses from Harbor Frieght:
Prior to that, I was taping amber acetate to protect the bulbs (single sheets at blick art supply for $2.80 per sheet): http://www.dickblick.com/products/grafix-clear-lay-assorted-colors/
This is what I can tell you about the original snap-on lenses. They were manufactured by a company in Mexico that has long since gone out of business. I searched high and low for new lenses and only found one, a red one, from a private person in Arkansas. No one has them, not Winnebago or Winnebagoparts, none of the auto parts websites that claim to have them. I spent months looking.