Cracked barrel staves?

I just picked up my first oak barrel, a 10-gallon rum barrel from a local distillery. Two of the staves on the top are cracked, and they look bad to me. The guy assured me that the barrel was watertight, and that the others he had on hand looked the same. Should I be concerned? I can't test for leaks since I don't have an appropriately-sized stopper on hand.

http://imgur.com/wnBYYub