If you look at that little sharp blip at the bottom of the chrome cover, that's where you have to take a grinder and reduce the overall length sometimes. I think having that crash bar on there makes it a completely different configuration as far as clamps. I recognize the pipe clamp (hi ya' pipe clamp), but not that crash bar connection. The clamps on my '59 also went below the sidecar mounts, I think. I'll look.
This is the way the clamps connect. They're sold as a set (VT 31-3989) parkerized, or chrome (31-0229) front clamp set. Everybody stocks them.