Most of us are getting the info from the book
"Colt: An American Legend", by R.L. Wilson.
This is a beautiful book filled with pictures of all know Colt firearms, from the first prototype revolver up to the mid 1980's AR-15 and Python. Most of the guns shown are heavily engraved presentation guns.
In the back of the book, Wilson has listed all know Colt serial number ranges for all Colt guns, up until the publishing date of 1985. As far as we know, there is no available information on Colt serials beyond that date.