Loquots arent true to type but my understanding is that they are close. I know one nursery that even sells seedlins as the named parent. I did a taste test with three generations of a friends loquots this year. The differences were barely noticable. The original parent was slighly sweeter, the seedlings slighly more tangy. Couldnt tell any difference between 2nd and 3rd generation.
Granted, some varieties might be less stable than others and itll probably depend on the presence of cross pollinators. But its reasonable to try seeds where plants are hard to get, like we do with jaboticaba and surinam cherry.