Yep. Too flat and balls go push side, too upright and balls go pull side. It's most noticeable in short irons (I've played games with a 64° wedge and lie angle), but it also effects long irons (not quite as noticeable).

Some will tell you 'check your divots'. I say, 'check your ball flight'. If you have a 'toe down' divot, but the ball goes straight, leave it be. Obviously toe down works for your swing.