Smelt are legal to use as bait in the waters that they are jigged from. Jig smelt in Champlain, use them there, jig smelt in Lake Dunmore use them there. Just don't transport them alive, unless you purchased smelt from a Champlain Zone dealer, which could only be used on Champlain.
I assume you can't jig smelt and sell then alive to Champlain dealers, but could probably still sell them dead.