Wanted - secret ID

[Mr.lucky]

I would like my secret ID checked, but I don't have a shiny with my UT(I have terrible luck(why did I name myself "Mrlucky"?)). I heard you might be able to do so with an AR or another external device, but if not, then it doesn't matter.

 

[SalamenceCommander]

Yes, you can find your secret ID with the use of a cheating device. Otherwise, you'll have to catch a shiny Pokemon.

 

[Kendrick]

Yes, you can find your secret ID with the use of a cheating device. Otherwise, you'll have to catch a shiny Pokemon.

Do you have to have a caught legit shiny from your game and THEN use the AR, or can you just catch a shiny from your game with the AR and find the the SID with the AR also?