If I use "Untamed Punch" with an undamaged Pangoro, does it still get the Confusion effect?
No, damage counters on your attacking Pangoro are required for both the Confusion and the extra damage.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)

Relevant cards

Note: All applicable cards may not be listed below.
SM6_78