Hard to say really because this is the first year of the iPad mini so you cannot say.They could sell out like hot cakes or they could be loads around and you won't have to worry at all.but if you have three stores you might be ok because you could try every store.For me then there only one store so i would be stuck.
I just order off the apple site easier no messing around then the nearest apple store for me is about 2 hours away so its just not worth getting in the car getting ready to go and waste money on fuel to get and there possible not been able to get one on the day.I wouldn't be happy traveling fours hours and not getting what i wanted.if i go somewhere like that then i would want a certain that i would get one but apple cannot say that i would get one on the day so i just use the internet easier.