I have a few more pictures. May not be much benefit as I can't help you out much with the metal tab placement. The wiring has been changed over the years to accommodate aftermarket sequential lights. Maybe the plastic tabs are in the same placement as original metal tabs? The original plate...
I'll attach a picture of the routing of the side marker light on my 68 Monaco 500. I'm not sure how much use it will be though. The harness was spliced and re-taped years ago to accommodate trailer wiring. This changed the shape and position of the wiring
