Strainst,
Set 1221 was cataloged between 1921 and 1926.
During the period from 1921-1924 the set was comprised of a 1218 engine, 1200 series baggage car, two coaches, a #90 station, semaphore, and tunnel.
Between 1925 and 1926 the set came with a 3011 engine, baggage, coach, observation, mail bag set, #90 station, semaphore, and tunnel.
As for number 1F3389 that is a Butler Brothers number that corresponds to years 1925 (and possibly 1926, as my data source does not contain the info for 1926). The Butler Brothers number for years 1921-1924 was simply F3389.
Since it is a Butler Brothers number, I can say that the items contained within the set would match the items described by American Flyer for that set.
NWL