I seem to recall seeing something like that for the dings on a gondola, but that was a stronger effect than is usual for a boxcar.
The most effective wavy panel look I have ever seen was
this HO car by Kevin Packard. Kevin does absolutely brilliant work and this one looks really convincing in the photos. Scaling it down to N seems like a substantial challenge, but the smaller scale could be an advantage insofar as the in-person effect goes, since the depth perception would rely almost entirely on light/shadow much like in a photograph or painting.
(For something like that in N scale, wire grabirons would be a must!
)
Ed
