At the end of the movie, the Full House of Sheriff Rockwell beats a Flush by Sheriff Porter, so She must need the gift book.
At the end of the movie they show the Sheriff Alden vs Sheriff Jo in poker, Alden has a full house Jacks full of 10s while Jo has an Ace high flush, they show Jo winning...but a full house can not be beaten but a Ace high flush, it has to be a straight flush.
The mayor suggests a couple of times that he controls the sheriff's budget. The sheriff's department is not typically under the town and mayor's control, but rather the county commissioners. The mayor may have influence, would have to get it approved by the county.