There have been no official annoucements in regards to the certification content being updated to clustered Data ONTAP 8.3. However, your instrucutors advice is sound. Unless you're planning on taking an exam in the new few weeks I would focus my studying on clustered Data ONTAP 8.3.
Updating an exam is a strenuous process that takes months of work so its impossible to time a new release to a GAs go live.