I've often found when I'm uncomfortable about telling someone that what they're doing is inappropriate (and what you've described is definitely inappropriate), it helps to phrase it as a question. For example, you could say something like:
"Shouldn't we have up-to-date ICD-9 manuals, just in case some of these codes have been deleted or changed?"
That will give them a chance to explain their reasoning for using out-of-date manuals, while bringing to their attention just one of many reasons why they shouldn't be using '07 ICD-9 manuals.
Coding books, medical coding books