Good job! That's a lot of Guardians! I ran all last night on my alts and, in 'Bow in the Blue,' would get between 16 and 24 Guardians total with a good group (~10 to 12 with a less-coordinated bunch).

One thing to note: you can't get less than 100XP from a Guardian. Skeletons, on the other hand, if they do drop XP they will definitely drop low amounts like 50, 70, 90, etc.