Yes. The Velocity Stacks should fit the interstate and as far as I can tell, Direct Line is the only one who still carries them. I ordered a set today.
BigBF does carry the front spacer and longer bolt for the gas tank which all models require when installing the V Stacks. He also carries a set of screens that you install in the stacks. Gives them a very nice look. Here's the link;
http://www.bigbf.com/