It is. The most important tables would be AccountItem/Account/Character/CharacterItem/Clan/ClanMembers/Friend and Login.
I done that for 2007 -> 1.5.
Ideas, you say?
Just use SQL statements to convert it.
Example:
PHP Code:
INSERT INTO GunzDB2.dbo.Login
(UserID, AID, Password, LastConnDate, LastIP)
SELECT
GunzDB.dbo.Login.UserID,
GunzDB.dbo.Login.AID,
GunzDB.dbo.Login.Password,
GunzDB.dbo.Login.LastConnDate,
GunzDB.dbo.Login.LastIP
FROM GunzDB.dbo.Login
Be sure to pay attention to the AID/CID's. If you ever deleted 1 row then you miss 1 CID/AID.