The answer, unfortunately, is likely yes. An entirely uncorroborated witness report isn't probable cause, but the standard for corroboration required is very low. There was a case Draper v. United States where an informant said "the guy's coming back from Chicago wearing suchandsuch clothes on September 9", and the police arrested him based on matching that description, with no corroboration of the underlying accusation that he was in Chicago to buy drugs.