[MF cowboy]

Yes $%#@ jobber parts supposed to fit but don't fit proper.
Don't think you can cut the knife one section short.
I would grind off the rivets on the last section and install the original 1/2 cleaning section and drill the knife bar for the extra hole.
Knife bar is soft like butter.
Couple new rivets and done.
I won't buy a riveted knife unless there was no choice.
As long as the drive end is spaced proper you can modify the far end with out issue.

 

[MF cowboy]

On this side of the pond I haven't come across a knife bar that was hardened.
I thought laminated knife meant riveted.
Sections here generally aren't that hard in the hole area. I remember drilling some out for larger bolt size if necessary.