Unless its a JIS keirin headset that you are replacing (which it is not), you're fine. Just get the new fork and headset aand install. Threadless headsets are easier to install and adjust--you only need an allen key.
No point, just curiosity about threadless headsets and stuff. They're still a mystery to me (even old headsets are pretty mysterious to me!). My current fork's fine and dandy, as far as I know, so I'm pretty sure I'll just pop a new headset on someday. Thanks!
I'm with genericbikedude, the old threaded headsets (well, actually, the old "7" stems are what makes the look) do look better. I was just curious. I'm probably gonna keep the old bike a little more traditional up there.