I tried long exposures with no gain and no darks using the Rising Tech Sony IMX224 eyepiece/guider cam to image the Owl Nebula, recently.  I was using it like I would one of my Canon DSLR cameras with long exposures at low ISO when shooting in bad LP conditions.

Hot pixels were worse than I thought, so I had to do some aggressive noise reduction.   Next time, I will definitely use darks based on this experience.  The camera has low read noise, but not low hot pixels with exposures this long.