What I would do is try to photograph the decals from the relevant directions straight on using a tripod, at the same identical distance, then "unwrap" the text using a program like hugin that can manipulate 3D projections. When you have a 2d unwrapped image, go to http://myfonts.com and figure out what font is used. Then use it or a free font like it to make a semi identical decal image, and print it out on a laser printer to gauge the size error. test it by wrapping iit around the frame and see if it matches. It may be close but t probably wont match. If that matters, redo it. If not, find a firm that makes decals and have one in the color you want made. Then CAREFULLY overlay the new decal over the old.