Yes, the fruit needs to be fully ripe even over-ripe so that the seeds are mature. It doesn't matter when in the season tho some prefer early as they think there is less chance of a cross. But you want from more than 1 fruit so early and mid season mix is good.

Yes it is rare - approx. +/-5% chance of cross.

Dave

If you don't have any bees/wasps around your plants, then
its closer to 0% chance. That's why I save seeds from
earlier set fruits. There are less/no pollinators around
when the early fruit sets.... at least in my NC garden.

Lee

Thanks for the info guys
Troy