
If people are nearby or passing then they are welcome to come and see the dogs, they may get to peek at the pups but the visit is about meeting the rest of the gang.
Anyone with a distance to travel I advise them to come after they pups are four weeks, as by this stage they are running around and playing and you can see the developing personalities.
As for choosing pups, this will not happen until they are old enough to be evaluated, at around 7 weeks.
So it depends on the purpose of the visit.