So, I have an idea, hare brained, but an idea none the less.

The goal is to duplicate the curved surface of the lens in a female mold so that the heated/softened plastic lens can be pressed and cooled/frozen to shape consistently.  Without a 3D model, the only available option is to make a mold from the real part itself.  I tried different ways to do this and failed miserably.  The main problem was that the clay/putty material I used kept sticking to the assembly itself and could not be removed without deforming the clay.  So, I thermo/vacuum formed the lens assembly to copy the shape of the lens.  Left the lens assembly in place protected by the formed sheet.  Use Crayola Air-dry-clay (if it is good enough for 5 year-olds, good enough for me) to form the mold, sticking to the thermoformed plastic shell.  Trimmed off the excess shell material.  Used clothe pins (they happened to be the right thichness) to center the softened plastic lens in the mold.  Heat up the lens cut out and pressed into the new mold with my other wooden mold.

The result is good, not excellent.  There were some lens details that did not come out as well as I had hoped.  The top ridge/crease was formed consistently along most of the length of the lens but not the full length.  As a concept, it is feasible.  I will continue to fine tune the processes, material and techniques until the formed lens fit precisely into the lens holder and continues the shape of the fender.