DF said in their video that even though it shows over 60 Hz the game isn’t actually running that fast. It’s below 60 at all times and the display shows higher numbers because of low framerate compenstation. This is where the display refresh twice or three times per actual real frame (you can see strobing if the display refreshes too slowly or it fluctuates too much), so the number on the display is 2-3x higher than the true in game frame rate.
I suppose it might be possible in some extremely simple areas to see a little over ~60 FPS, but DF confirmed their >60 FPS figures to be compenstated and not true, so it seems like it would be very rare if it does happen.