C# - Excel: Is the cell object a COM object?

Programmer Question

Working with Excel interop, I'm trying be very careful about not implicitly creating any objects (c.f. two dot rule) and ensuring that everything is properly released.

If I create an System.Object from a COM object property, is that object a COM object? To clarify, take the case of the cell object below. Do I need to call Marshal.ReleaseComObject(cell) or not?

public static float RangeLeft(ref Excel.Worksheet sheet, int row, int col)
{
    float returnValue;
    object cell = null;
    Excel.Range range = null;

    try
    {
        cell = sheet.Cells[row, col];
        range = sheet.get_Range(cell, Type.Missing);
        returnValue = (float)range.Left;
    }
    catch (COMException comex)
    {
        Debug.WriteLine(comex.Message);
        throw;
    }
    finally
    {
        if (cell != null)
        {
            Marshal.ReleaseComObject(cell);
            cell = null;
        }
        if (range != null)
        {
            Marshal.ReleaseComObject(range);
            range = null;
        }
    }
    return returnValue;
}

Find the answer here