Factory or not Frame Humps

[AlaskaK10]

Hi All
I am working on my short wheel base 1966 K10 frame. I have two symetrical humps on the top of each frame rail right where the rails go from straight and start to bend inward toward the front for the engine. It appears to me that when the frame rails were bent inward at the factory the metal humped up both in the same area. I have another frame and from a long bed that does not have thease humps though any thoughts?

[raidmagic]

They sure look symmetrical and no corresponding humps on the bottom frame rail. Probably nothing to worry about. Someone with more knowledge than me will chime in though I'm sure. I'll look at my frame tonight and see if it has those or not.

[AlaskaK10]

My long bed frame same vintage does not have them. Maybe a different plant. The measurement data I have found says 54.5 inches from core support center hole to first cab mount center. This measurment checks out so has to be a factory thing.