I'm getting concerned that I'm going to throw you off.....so I think we need a third party here to also give measurements!
My new sill is long in the front to back (front of truck to back of truck direction) compared to my old sill. So I've cut my bed some.
When I line up my old sill I'm...
Check the front (forward) lip also. My sill patch doesn't line up with the ribbed bed length
correctly. I have mine apart at the moment (just the sill off) and have
let it sit while I think about what to do. I can probably jimmy up my old sill and get any
measurement you need. Mine is...