Sorta. It's also used to steady the projectile in the right direction. Obviously, we can't simulate the imparted spin a rifled barrel would generate on the missile, and the barrel is a bit on the long side (aesthetics over function). Also, as the missile accelerates down the barrel, i'm thinking its speed would exceed the breaking speed of the barrel lining panels and break them on route, causing a barrel explosion.
That being said, i'd definitely have a short barrel, as just having a hole for the missile to exit from, the missile could go anywhere after launch