Victoria Header

[CA Victoria]

I ran into an odd duck the other day. The original header that I have is narrower than the replacement offered. The additional thickness will not allow the header cover to seat back in it's original location. With that said, there must be a physical difference with the body construction or the header covers?
Steve at Classic Wood Mfg said he has run into a couple like this.

The header should be the same for both the Steel, Leatherback, and possibally the slant windshield sedan. I cannot find any information in the Victoria Association's archives to address the difference.

Can anyone shed any light on the differences.