Two horses were used throughout the series to play Argo. In the scene after Gabrielle gets caught by the guard, Xena is seen in a stable looking for clues. She stops to pet Argo and then moves past another horse that is stabled. The other horse is also used for Argo and looks identical, especially in coloring.
Timeline flaw: s1.e13 The Athens Academy of the Performing Bards, when Gabrielle and Xena are apart, happens before Gabrielle meets Meleager. They meet in s1.e18 The Prodigal. If Meleager has been in jail since he was discovered with a murder weapon, he and Gabrielle would never have met.