Is it recommended to raise one's hands when saying "Ameen" to the preacher's supplication on Friday?

The default is to raise one's hands when supplicating, except during the Friday sermon. In the Friday sermon, the Sunnah is for the خطيب (preacher) to only point with his index finger, and it is disliked for him to raise his hands; the attendees follow his example. An exception to this is the supplication for rain (Du'a al-Istisqa') during the Friday sermon; in this case, it is Sunnah for both the خطيب and the attendees to raise their hands.