@corbettclassics I've checked all Bianchi catalogs from late 1910s to early 40s.
You were right: all Bianchi track bikes until the 1929 have rear facing dropouts. There's a couple of years in which I honestly don't know how they were made.
In 1933/34 Bianchi introduced the road racing Bovet model with new designed dropouts and that style of front facing rear dropouts were used in track bikes as well until mid 50s - even though there are frames from 1953 circa with rear facing dropouts.