After thinking about it, a local guy had a 318/auto triple-green '70 that had the V8 fender emblems. I'd totally forgotten about that car. Long story, but I still don't know exactly what the fate of that car was... there are differing stories between the two brothers involved. Regardless, the V8 emblems were a sure sign of a two-barrel engine. They were not used on any HP-equipped models in the 6 or 7 years they were used.
You're right, though, the four-speed wasn't available with the 383-2V either, meaning this car would've originally had a 3-speed. '66 was the last year you could get a four-speed behind a non-HP engine (or Slant Six) until 1975, when the OD trans showed up in the A-bodies. I've seen a number of supposedly original 318/4-speed cars over the years, but not a one of 'em has ever been backed up by the data tag, nor has such a car ever been documented (of any body style)... but it was apparently a very-popular swap when junkyards were filled with donor cars.