Just run the CheckDB. If it was a NC index I'd say drop and recreate, but a cluster that's a lot of time and a lot of log usage, you're rebuilding the entire table and every single nonclustered index twice if you drop the cluster and recreate. There's no data loss potential here.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability