It is a 80% round signal from a mid 70's KZ 1000. I had templates with me so I knew I could make them work. I used the original signals from the bumpers, drilled a hole with a hole saw for the light to pass through. Secured the new lens to the old one with a small nut/bolt and sealed it all up with clear silicone. The bumper shock holes needed very little modification to work. The fit is almost perfect. There is a gap about 1/8th inch on right and left side and no gap vertically. I made it fit very snug. I don't have them permanently installed as of yet but I don't see any issue in doing so.
Here's pix, total cost $10!
Whaddya think?

got them!

Piggy back style

looking down on it

mocked up

straight on