Swapping emails last night with Duane, the Hackenberger auction was mentioned. Here's what he had to say about the one that was near him after I told him another dual carb Darrin turned up.
"Russ, (forget his last name), had the dual carb intake and I doubt that he went to Brazil, I'm sure it came from KF right here in the USA. He also had the factory "much better design" crossmember that KF engineered, but didn't put on any Darrin's other than his car. He also offered engineering specs and drawings of the crossmember that he offered Darrin owners. Russ Spaulding. He attended the National here, but had no interest in our local club what so ever. He really needed help with his Darrin to run right, but never reached out to any of us. He was an official photographer for KF, if you didn't know."