Actually, the "prongs" at the end of the spring snag the underside of the perimeter trim (around the opening of the headlight bucket). You could grab that spring and pivot it upwards (left side being the "hinge") and free it from the trim. The threaded hole in the bottom of the bucket holds the retainer screw that extends up (just in front of the rolled portion of the spring) and engages a hole in the clip that's riveted to the bottom of the reflector (at the 6 o'clock position). Once the screw engages the hole in the clip, the reflector cannot move in or out, and thus the lense is firmly held in place. Unscrew the screw slightly, and the shank lowers out of the clip hole, thus freeing the bottom of the reflector. You can then push inward on the bottom of the lens and the whole lens / reflector moves inward. This allows the top of the lens to drop down and be lifted out of the bucket. It's a fairly weird system, but somehow it works.

As you can see, the bottom spring is the first thing to rust out in the whole headlight. Duke Marley had a whole bunch of them reproduced maybe 20 years ago and they eventually were all sold out.

Thanks for the info Jon. My post should have gone in the Hudson forum, rather then 'suggestions and comments', so I reposted it there. Sorry for any confusion. I hope the photo is useful to someone.