Roof line changes?

[Dub and Bubber]

I've just looked at an early bay properly for the first time having been in cross over world for some time.
Do early buses have a mid-roof side to side channel that isn't on cross overs and lates?
It can't be standard surely ... Don't see it in photos of other 71 US buses ...

 

[davidoft]

My 78 van has it

 

[sparkywig]

All tintops have it, the roof profile never changed during production.
The swage line is about 3/8 from the front rather than halfway.

 

[Graham L]

Only vehicles that dont have it are Sunroof Deluxes and pop top Westies (same roof pressing) as it falls where the cut out is on the roof

 

[Dub and Bubber]

Thank y'all ... Must be that I've also only ever seen pop tops close up, and never noticed it in photos of tintops