Kimble throws the bag with the rattlesnake in it through the passenger-side window of Walker's truck, but seconds later, when Walker gets into the truck, the window is rolled up.
In the Flashback episode it's Texas Ranger Hayes Cooper, not Ace Cooper.
This episode was the first appearance of 19th century Texas Ranger Ace Cooper. In his episode we learn that Cooper was killed in the line of duty while trying to recover a cash of gold stolen by a ruthless gang. However in the last season of the show we learn that Cooper not only survived but took over as the sheriff of a small town and has a family (this family will eventually lead to a Great Great Grandson that Walker helps at the beginning of the season). Along with that is two different tellings of how Cooper became a ranger. In the first version he was avenging the murder of his parents and was offered the badge. In the second he was a bounty hunter that took over for a ranger that was killed by outlaws.