Yes, you are at risk. You would be able to restore to a point in time until your last archivelog.The last archive log, that was active while RMAN finished working, will not be in the backup set.
See Jared example in this thread. Adar Yechiel Rechovot, Israel Joel.Patterson@xxxxxxxxxxx wrote:
Hmmm, now I'm wondering. I only have ... 'backup database archivelog all;' Does this mean I am at risk?