Introduction dates of different 74xx or 40xx chips?
To my knowledge, there is no official list of introduction dates for 74xx and 40xx devices.  It is possible however to show that a device was available by a particular year, by virtue of it being listed in the catalogues in that year (and later years if not discontinued).

This is the May/June 1966 TI price list (PDF) which lists their semiconductor products at the time of printing, and shows what 74xx series devices were available at that time: 



Quite the range, and only $85 (2017) dollars for a 7474 D flip-flop!

Bitsavers also has copies of the 1967-68 TI IC catalogue, the 1971 TI IC catalogue and the 1976 TTL Databook (a catalogue and datasheets for their parts).

Using these, you can set an approximate window on the release of a part -- a part which is listed in the 1976 catalogue but not 1971 catalogue can be assumed to have been introduced after of the printing of the '71 catalogue.

Some things to keep in mind.  Especially in the 1960s, things that were listed by manufacturers were not necessarily actually available on the market at the time of introduction (unless you were the US government building an ICBM), due to limited production volume.  Similarly, parts may have been available for direct order after being "discontinued" and delisted in the catalogues, particularly with the Databook which was intended as a reference for new designs.