I found a little more on the topic in the linked article. It is interesting to note that he was giving a speech on the Monday in observance of Martin Luther King Jr. Day, so it was not a regular church service. This would definitely lead one to believe it was indeed in his official capacity as Governor of the State of Alabama.
In his speech marking observances of the Rev. Martin Luther King's birthday in the church where King was once pastor, Bentley also told the crowd, "I think that Dr. Martin Luther King was one of the greatest men that has ever lived."