That's right; also a '0' cost figure means that no link status report has been received for that link yet (or the threshold number of missed status intervals has been exceeded-- the link has gone stale).
Age counters get reset to '3' every time updated status has been received. That's why active links usually display age 3; age 6 is the stale threshold. Age counters in the 0-2 range are used when new links are being established.
