Использование синхронизации Interlocked.CompareExchange с объектом синхронизации в обработчике Timer HandleElapsed

Я читаю пример MSDN http://msdn.microsoft.com/en-us/library/system.timers.timer.stop.aspx

В примере с timer.stop я подозревал, что его способ использования Interlocked.CompareExchange неверен.

private static void HandleElapsed(object sender, ElapsedEventArgs e)
{
    numEvents += 1;

    // This example assumes that overlapping events can be 
    // discarded. That is, if an Elapsed event is raised before  
    // the previous event is finished processing, the second 
    // event is ignored.  
    // 
    // CompareExchange is used to take control of syncPoint,  
    // and to determine whether the attempt was successful.  
    // CompareExchange attempts to put 1 into syncPoint, but 
    // only if the current value of syncPoint is zero  
    // (specified by the third parameter). If another thread 
    // has set syncPoint to 1, or if the control thread has 
    // set syncPoint to -1, the current event is skipped.  
    // (Normally it would not be necessary to use a local  
    // variable for the return value. A local variable is  
    // used here to determine the reason the event was  
    // skipped.) 
    // 
    int sync = Interlocked.CompareExchange(ref syncPoint, 1, 0);
    if (sync == 0)
    {
        // No other event was executing. 
        // The event handler simulates an amount of work 
        // lasting between 50 and 200 milliseconds, so that 
        // some events will overlap. 
        int delay = timerIntervalBase 
            - timerIntervalDelta / 2 + rand.Next(timerIntervalDelta);
        Thread.Sleep(delay);
        numExecuted += 1;

        // Release control of syncPoint.
        syncPoint = 0;
    }
    else
    {
        if (sync == 1) { numSkipped += 1; } else { numLate += 1; }
    }
}

Мой вопрос в этом блоке

int sync = Interlocked.CompareExchange(ref syncPoint, 1, 0);
if (sync == 0)
{
   // lots of code here
    syncPoint = 0;
}

Должно ли это быть как

int sync = Interlocked.CompareExchange(ref syncPoint, 1, 0);
if (sync == 0)
{
// lots of code here
   Interlocked.CompareExchange(ref syncPoint, 0, 1)
}

Поскольку исходное назначение syncPoint = 0; не является потокобезопасным. Я прав?

ОБНОВЛЕНИЕ:

Я обновил пример, у меня нет вопросов о возвращаемом значении ComareExchange, мой вопрос касается назначения переменной syncpoint в конце этого блока if. Блокировки на нем нет вообще.