Does seasoned cast iron still need to be oven dried?
Any exposed, non-coated part of a cast iron pan will be subject to rusting. Oven drying drives off the water before the reaction can happen to a noticeable amount. 

The seemingly smart alec, but actually serious answer is: try to not oven dry it. If it does not generate rust, then it is seasoned enough. If it rusts, then rub again with light oil and oven dry. I tend to lightly wipe all over my cast iron a bunch of times until I get the entire pan nicely seasoned.