No. Not to give you an abrupt answer, but no. Lead shot is MUCH softer than any steel barrel, whether it is a smoothbore or a rifled barrel. If it IS a rifled barrel, the pattern from shot will suck INCREDIBLY- the rifling imparts a spin that makes the shot pattern resemble a doughnut. Clean the barrel thoughly if you have signs of leading.
On the other hand- if you have ALREADY shot it, sorry, your shotgun is ruint- box it up, ship it to me postpaid, and I will dispose of it and never let anyone know of your shame. Deal? I won't even charge you for the disposal, 'cause that's just the kind of guy I am.