captjns,
Can you tell me where you found that information on the fuel tank feed for the 727?
I have worked on 727's nearly my whole career (13 years) as a Flight Mech and Line Mech here in the US and abroad and for many different airlines and operators and I have never seen one that could feed from anything other than the center tank.
This includes the -100, -200 and the -200Adv with the intergral #2 tank as well as the bladder tanks on the old basic -200's and -100's.
quoting Benson's website "The APU uses fuel from the number 2 tank"
http://www.boeing-727.com/Data/systems/infoapu.html