That's very likely... that is to say, the internal energy portion is. That's the important and significant part of KHBD after all (unless you think that the original eunuch used needles as his technique).
However, the 72 strokes were clearly not very good in themselves. It was the extreme speed that made them deadly but even then LHC was able to compete with the strokes and then even defeat the strokes despite the speed indicating that the strokes were a handicap.
Since Lin Yuantu dominated wulin and was clearly a martial arts genius, I do not believe he could possibly be limited in such a way. Thus, I conjecture that these strokes were to hide the true nature of PXJF (which is the internal energy driving incredible speed).
This is supported by the fact the entire wulin thought that it was the techniques of PXJF that was amazing. That the Lin family were incompetent in learning the technique. That they (e.g., Qincheng School) copied the strokes imperfectly. They only thought they needed the "xin fa" and perhaps an internal energy method.
Nobody had an inkly about the speed of PXJF.
Combine this with the idea of formlessness being the realm of masters, and it becomes a short hop in thought to come to the conclusion that Lin Yuantu had some formlessness and was able to simply utilize Sword Intention with his speed. The strokes then cease to matter for the result and served to give observers something to see. By using only just enough speed to win, they would never suspect Lin Yuantu's real secret was speed.