What kind of radio codes do you think you'll need to know, where is your internship being done at? DPD doesnt really use codes as often as other agencies, and there are very few that are used. And "10" codes are never used.
To be honest - more important than knowing the codes is knowing proper punctuation / use of capital letters / etc. I was just talking to one of the police academy teachers at Lansing Community College the other day and the thing he said that literally fails most recruits is their inability to write proper reports.