Apart from all that, even the 16th century originals were not medieval...

There is but one house in market square that dates from the middle ages, the Tempelhaus (mid 14th century), and this one survived World War II and is still authentic. The others are, as said above, reconstructions.

Hildesheim has one unique medieval gem, though, which is really worth seeing, and that is the church of St Michael which celebrated its millennium last year.