Les at Classic Datsun Motorsports has a mold for 610 front lips. Adam Carolla has one on his Bob Sharp 610
https://www.facebook.com/pages/Classic-Datsun-Motorsports/150080191851119
This video from the last month's inaugural Spring Classic at Laguna Seca has quite a few 510's in it, a total of 12 signed up.
https://www.youtube.com/watch?v=U0kL9G8ZKGc
I saw this car in person at Laguna, and it looks great! FYI - the car did not come with the above mentioned missing trim. I was clear that Les and the owner eventually want to get everything correct on this 610, and they are looking for these rare bits: I know that any leads would be most appreciated.
I am fairly sure that is Rob McFarlin of FAR Performance driving in the 1976 National Championship runoffs at Road Atlanta. Unfortunately, I believe that particular B Sedan 610 no longer exists.
Nisman, that's a very clean and complete SSS you've got there - well worth your effort to take delivery! It's good to know that those tail-light bits are going on such a nice car. Looking forward to your progress pics.