I don't have C2 licence so I can't tell you that it's posible to put your sprites in family and then set Text to "Family.Number.of.Object" like in CC - in CC that option you can call but it's not working like meany things in CC.
If that's not possible in C2 you can set text to 'objectcount'(from system) (all object that ara on layout and exclude those that are not sprite and counts as those that are on layot even if not visible. Some of these are:
text, particle, tilebackground,canvas, array, ok button, dictionary, fuction...
find out the rest that you use in your project and for total number of object substracte each of them
'objectcount'- number of object that are on layout (visible or not)and not sprites = number of sprites
that's all I can think of