47-55.1 cab and bed floor parellell?

[edgeleycanuck]

I have been assuming that the bed floor and the cab floor should each be level in relation to the frame and to each other (parellell ). However things don't look right....the back of the cab looks low (as though the frame was bent down in the middle of each side of the frame).
I have used levels including a rotating laser and if I level everything it looks wrong.
I just noticed today the rubber fill strip between the cab and the running board appears, by a lifetime of use, that the cab is not level with the running board. The running board has to be parellell to the box or the aprons would not fit /fill correctly. Any thoughts or measurements any of you may have are welcome. ..I'm stuck