if they're both NO and wired with pull-ups, they're basically a (N)OR gate... if you push either one of them, or both at the same time, the interrupt pin will be pulled low, only if both are released will it be high...
that, of course, won't work for the case where one switch is already pressed, and the other is toggled on/off. if you want to detect that, you should use an XOR gate. the only type of change that can't detect is the case where one switch is already pressed, and then that switch is released at EXACTLY the same time as the other is pressed. however in reality there's no way you could press the switches that accurately and quickly so it should work fine.
just some food for thought.