I went to an indoor rock climbing gym for several years and had the opportunity to climb outside on a handful of occasions.
Climbing a large, imposing rock seems to be the best analog to a Pleistocene/Paleolithic "pull-up" (although I suppose tree climbing would work as well.)
When facing the option of either falling down a rock face, or making it to the top, I most definitely did anything and everything that I could. If "kipping" was an option, I would have taken it gladly. As it was, I performed a move that could more accurately be described as "the beached whale".
This involves applying as much bodily surface area as possible to the rock and, inch by inch, shimmying until enough body mass was over the lip to permit a muscle-up-esque top-out of the boulder.