1930-31 Closed Cab Pickup Roof Rear Header Question

[Zener424]

Hello fellow Model A enthusiasts, I am replacing the top wood on my '31 Closed Cab Pickup and have a question regarding the rear wood header. I picked up the wood kit at Hershey several years ago, & I'm just getting around to installing it. The new rear header has a groove cut into the top of it. For those of you that are familiar, does this seem correct. The header that I removed, has no groove, the top of the header is flat. It seems that with this groove, the metal nailing strip of the body will not lay properly as I attempt to nail it in place. I would appreciate your comments, thoughts & a photo of a header would be nice. Please see the attached photos of the new header in place and the old header removed. Thanks, & everyone have a great day...Phil