the object cannot become fake depending on how or how much was it sold for. It is either fake, properly restored antique or improperly restored antique (including mistakes like altered or mismatched items). Good/proper restoration should not be obvious. It should be just as original and properly belong. The replacement, if done correctly, would not make the whole item fake. it's commonly done with damaged antiques of all kinds. Most museums do it. They employ professional restorers and some do repairs that are totally invisible, they are not fakers or an item becomes fake after that. Apart from temporary effect on value, the item gets a new life and remains what it is, IF properly done.
As for above items, one is restored and another is mistake. just because they are sold as 17th C genuine antiques does not make them fakes. It'd make a buyer as such if he/she agrees with the seller
Just my opinion