>It would rely on a bit of luck with the timing – if the capture started at the maxima or minima there would be no difference in the pulsar’s brightness between the frames. Also I’m not sure you could trust the camera to run at a constant speed and not drop frames whilst capturing.
I think provided the exposure time is short enough (less than the max to min), the frame rate just needs to be known and stable (and just different from, even slower, than the pulsar). You can then assign a relative phase to each frame and stack the frames in groups with similar phase. A quick initial test would be to test if the pulsar can be seen in a simple stack of short enough exposures. If so then seeing the pulses should just be a matter of picking the right ones out and stacking them. In theory I suspect you could even find the pulsations without knowing the period.