I own three 246 GT models, all still fitted with their original gear shift knobs. They are all the same as the one in my photograph. If you care to look at Matthias Bartz very detailed Dino Compendium book you'll see the same shift pattern knob as mine in every one of his 246 models. The 308 also used the same one as the 246 whilst the 206 has a different shaped gear shift knob entirely.
I'm not familiar with the Fiat Dino models so you may well be correct on those but it most certainly is not correct for a Ferrari Dino 206/246 or the 308.
Current: F50, 246 GT (x 2), 246 GTS
Past: 360M, F430 spider, 430 Scuderia, California (x 2), 458 Italia (x 2), 458 spider, 246 GT