This flag was used in October 29 2004 and March 28 2005 videos. The text is written in Naskh script. Neither this version nor other versions of the AQI flag listed below used elaborate calligraphy. This is probably because they are handmade (which may also explain the differences between them).
In a flag used in January 2005 the w:Shahada is not split, and the organization name is written in Riqa'ah script.
In an earlier flag used in October 2004 (first video of Shosei Koda) [1][2] the text and circle are white, the Shahada, written in Riqa'ah, is not split, "Tanzim Qa'idat al-Jihad" is in Naskh, and "fi Bilad ar-Rafidayn" is in Riqa'ah.

In yet another flag (date unknown), all the script is in Riqa'ah.
Own work
Axiom292