Yes, I would recommend quarantining every fish that you get no matter where they came from. I would also recommend treating all fish prophylactically with copper. It will save you a bunch of trouble later on.
Trust no one. For a 40B you might be able to argue that since it's such a small tank you could risk it because dumping everything out and starting over if there's a problem is so easy. But, QT in a 10 gallon sterilite tub or 10 gallon tank with copper or chloroquine is just as easy, so why not start out knowing your fish are as healthy as possible before they make it into their final home?