Just traded up to an 04. I didn't take the under bed mounts for the 5th wheel rails out of the 99 because 1-I figured they'd be diffrent for the 04, and 2-the nuts were on them so tight that I couldn't budge them.

With that said, does anyone have a part number and location to order 5th wheel rail underbed mounts for my 04?

I have everything except the frame/underbed brackets.

 

You might check with a trailer shop and see if you could get the part from them.

 

Most bed mounted rail kits are universal - you just get the 2 rails and the 4 "L" brackets with the hardware in those kits. The standard rail kit is the same for the 2nd and 3rd gen. You could move up to a rail mounting kit that uses truck frame specific frame plates that snadwich the frame rails (which are vehicle specific) but if you aren't towing heavy you can do without the added cost and complexity of that type of rail mounting.