68 2wd Burb Body to 72 4wd Chassis?

[Killer Bee]

Howdy Folks, couple of questions for the experts;

• will a 68 2wd Suburban body directly bolt onto a 72 4wd Suburban frame?
  
• what are the required modifications to the floorboard, hump change?
  
• anything seriously different in body panels?

I have a complete 72 GMC K1500 Suburban rustout and I'm looking at some earlier GMC donor bodies..

asking if there are any major body modifications required beyond the obvious nut-n-bolt work..

I scoured through some older threads but I'm not finding specific differences outlined respect of year model and 2wd to 4wd addressed..

I'm already researching the vin issues but looking at clear title donors only and not interested in selling anything complete..

even the briefest replies or links to specific threads all appreciated, thanks in advance!