I'll consolidate a couple of threads here with a history of the 737 involved in the incident at BUR last night:
Airrcraft type: Boeing 737-3T5
First flight: December 21, 1984
Serial number: 23060
Line number: 1069
Sold to Orion AL on January 29, 1985, registered as G-BLKB
Orion merged with Britannia on January 26, 1989
Morris Air of SLC leased aircraft on April 11, 1993, and registered as N753MA
Morris merged with Southwest on or about June 10, 1994, and Southwest then reregistered aircraft as N668SW.
To answer the question about the number of 737-300 series aircraft built, the answer is 1,113.
Thanks to Bill Harms web-site, and SC airliner lists for the above info.
Tom in NO (at MSY)