Always put new bearings on new races.  I would examine the bearings and races carefully if you are considering reusing them.  The race will usually tell you more than the bearing.  Really look at the surface and I'll be you see an area of discoloration where the rollers from the bearing ride.  If you look at it closely enough (probably need a magnifying glass) you'll see the surface is pock marked with tiny places where metal has been removed or corroded out of the race.  That damage is from moisture and acids in old grease.

With bearings I clean them completely then spin them with air.  It sounds odd, but I can tell by the sound they make whether or not they're any good. 

Thanks guys!