
I didn't have an x-ray done to know the number of puppies. I would, however advise having one if the male was significantly bigger than the bitch (if I were ever in that situation!) rather than risk her being in serious trouble trying to deliver whelps who were just too big to be safely delivered, naturally.
If the labour was difficult but without a C.Section, I might opt for x-ray, to confirm whether or not the bitch was empty. And ditto for a small (one only) litter that didn't progress to a normal delivery, prior to opening her up ('section).