p much yeah. everything you battle counts towards evs, so you'll have a lot of random evs in things. you should hope that you haven't battled over 252 times already in order to get your speed to maximum, if not just grab ev reducing berries and work out how many evs you need to remove by pokecheck or something along those lines.
QQ for you if you know. I am raising up a Deino to level 30 so far liking its stats can I get its maximum possible Spd stat or such level by lv 50 or do I need to start Ev training from level1 for best results?