I mean the Nat. Dexdo you need the dex to get the DOGS?
If you want a good dog, get one off colo. No matter what the dogs in FR and LG have crappy Ivs as well as the Latis that aren't from Southern Island. 20 in hp, 3 in atk, and 0 in everything else.
but thats just for running legendaries right...?
The Ivs/Natures of Latios/Latias and the 3 'Dogs' are set when you first start the game.
Also the 'Dogs' tend to have really low IVs in everything but HP, and Latios/Latias have just random IVs