Peterbilt 359 - quick 5th wheel question

I would say more than likely it should line up with all the bolt hole so long as the donor truck has the old style spring hangers similar to your 359.the older suspension hangers raise up higher on the frame requiring the slider frame being notched over the spring hanger

 

holland slider?

 

If the price is right and the slider is good and hasn't been set in one spot since new it shouldn't hurt to notch it with a torch most of those bolt holes line up with cross members inside the frame . If a hole doesn't line up definitely don't drill the truck frame,drill the slider frame

 

Why not knock the pins out of the table or fifth wheel plate and leave the frame where it is. As far as your other post on the small cam. As I remember some guys were running 300# fuel pressure. That is pretty high. Seems to me we used to have the pump set up 15%, which would put you around 200#. There is another site that may offer more info and maybe someone reasonably close that could help you. thedieselgarage.com