I could be wrong here, but I believe that the cuda340 & cuda383 package were available from the beginning of the 1969 model year. I do know that the cuda440 was a mid-year introduction with the first batch being tagged as C01 (Dec 68) although their actual build date varied as they were a "run".
Attached are a couple of photos of a 69 Barracuda sales brochure, and in it, there are both cuda340/383 models. Since it is the only 1969 brochure I have seen avail. it seems unlikely that they would have offered the models in the brochure but not produced them for half a year. This brochure does not list the 440 as being optional or available.
Grant