Yes the peels are on the no-no list (however, cooking the peels apparently will nullify the toxic element in them) >and when something is referred to as "toxic" this does not necessarily mean they will drop down dead in a couple of days from it, but (dependent on what it is and how much and how often eaten) that it can damage the birds in some way or cause organ damage in the long term for instance.
There are so many things you can give your birds for "treats" that are not on the list of no-nos why risk it? (remembering that what a bird considers a treat is quite different than us!)
Unless these are organically grown potatoes there will also be the issue of preservatives etc. .... but to answer your question I do not think this one boo-boo will do any damage .