In short: Yes. So long as the other Pokemon in your party were not fainted, they gain the full EV effects of whatever the lead Pokemon defeated when EXP.SHARE is turned on.
Per Bulbapedia, The formula that determines your stats is:
HP = ((((2 * BASE + IV + (EV / 4)) * LEVEL) / 100) + LEVEL + 10)
Other Stats = (((((2 * BASE + IV + (EV / 4)) * LEVEL) / 100) + 5) * Nature)
What this effectively means is that the total bonus Effort Values provide is distributed out across all 100 levels. You don't get the whole value all at once, it is metered out until the full value is reached at lvl 100.
If you trained speed to 200EVs (+50 to speed), in addition whatever speed it would normally gain every level - every second level that value is effectively raised by 1. It isn't very noticeable on any given level up, but over the course of several levels it starts to add up.