'73-'87 Crossmember In A '70?

[Stepsides 4Ever]

Ok, I have a fair understanding of what fits what as far as converting my 1970 SWB Stepside to later model disc brakes, but will the crossmember from the '73 to '87 bolt up as easily as the '71-'72s do (slight modification to bolt holes), or is this a whole different animal? Sure seems like it would be easier to remove at the bone yard and disassemble it at home with my air tools, but I don't want to pay for the crossmember if I can't use it.