If the male pollinates the female your going to have buds with seeds. And if youve got this your either crossing strains to get yourself seeds or you dont know what your doing or you made a honest mistake. Usually the buds are dried superfast and you come out with shitty weed which is swag. But its possible to get some mids if you dry and cure the buds correctly.
You can take a bagseed and grow it into some nice good bud if you chop any males before pollen is released. So no, swag and good nugget come from the same plant but along the way things went bad and out came swag
So yeah the guy who told you that had grasped the concept.