Yes, some of the old guys had everything figured out for sure. I've met several over the years. There are no male or female fruit, your father saved seed the way most seeds were, and still are saved.. by selecting the bigger fruit. That's a good way to select for seeds, but it is known now that the bigger fruit on some beefsteak varieties can contain cross pollinated seeds. All maters are self pollinating, but the first blooms on some varieties have what is known as an exerted stigma, and those flowers can become cross pollinated by bee's especially if more than one variety is being grown. I try to save seeds from as many selected plants within the population as I can. Say I have 20 plants of a variety growing. I will look for the most productive and healthiest plants as the season goes along and mark them for seed harvest in the fall. I always save seeds from the smaller late set fruit because of the exerted stigma condition mentioned above. It's just the opposite saving bean seed. I never pick the first beans on the plant, I save seed from those as they are less likely to be cross pollinated.