Ninja'd....
Yes, you could use instance variables. Just make one button sprite, and add an instance variable (text) to them. You could call it "whantnot". Then create 4 copies of the same sprite on your layout, change each buttons whatnot property as you deem fit. For example you give two of them health and mana values.. then later in events:
mouse on clicked button
button.whatnot="health"
give health potion
else if
button.whatnot="mana"
give mana potion
Hope this helps.