There is debate about the exact number of first printing copies available. Some say 10,500 while others say in the 700 range. The latter of the two does not make the most sense based on the amount of first printing copies available on the market. It is safe to say that the 10,500 number is most accurate.
When examining a first printing of Harry Potter and the Chamber of Secrets, there are multiple issue points present.
The number line on the copyright page reads: 10 9 8 7 6 5 4 3 2 1
Bloomsbury as the printer
The cover includes a quote that reads 'Inventive and action-packed' The Bookseller
Dust jacket (first state):
Front inside flap, paragraph three, "Harry Potter and the Philosopher's Stone" not italic
Front inside flap, paragraph three, no comma between the name "El-Shawk" and "Age 11"
Front inside flap, paragraph four, "Harry Potter" not italic
Front inside flap, paragraph four, no comma between the name "Farrant" and "Age 10"
*The first state dust jacket errors were corrected at the seventh printing of Harry Potter and the Chamber of Secrets.
*It is rumored that only 200 second printing copies were printed