A small amount of air leakage from the front bearing is normal when turned over slowly. A small amount of fuel is also normal to an extent.. What I would recommend is that you remove the back cover and inspect the bearings for rust. If you fine some on the rear bearing, rest assured that it's on the front one also!
If you think you need new bearing, you probably do! Stock bearings can be had, but are usually more expensive. Boca Bearing has a high speed bearing set that is very cost effective and of good quality. www.bocabearings.com
I hope this helps.