You are confusing chassis #'s with model designations. "105/115" refers to a chassis type shared by coupes, spiders and sedans built from the mid 60's through the mid 90's. So the '66 sedan that Alfa69GTV1750 offered is a 105.
What you should be requesting is a 105/115 coupe. The earlier models, called "Sprint GT's", displaced either 1600 or 1750 cc's and were designated 105's (as were the spiders and sedans of the same era). And the later 2L cars, called "GTV's", were 115's (as were the 2L spiders and sedans).
There are a number of books that explain this in more detail. My favorite is "The Alfa Romeo Buyers Guide" by Joe Benson.
Contact me at [email protected]. Titles in hand for 1971 GTV 1750: 102K, Dynamat and sound proofing in cabin, RED, Fast Road Suspension kit from Alfaholics (poly bushings, entire susp. replaced, new radiator, battery, top end rebuild less than 16 months, garaged kept, 2.0 litre with dual Webers (40), New exhaust front to back, 10-12 K away from being number 1 car (for body and paint). Love car but have new 4C and space. Reach me at [email protected]. (30K into it). Won autocross by 10 seconds in PIT at AROC Convention a few weeks ago, video available. I am a driver, car rocks! 3rd place in my group on racetrack. Drove to PIT and Back no issues. -Jose