Is it the same for calligraphers to hold pens?

Of course it is. However, calligraphers of different times hold pens in different ways. For example, people in the Jin Dynasty held pens in the same way as we did. In the Tang Dynasty, the structure of writing brushes was different from ours today. The finger position when holding a pen is the same as that of a calligrapher (as far as today is concerned), except that some people hold the pen high and some people hold the pen low (beginners hold the pen low).