Hey Chronic!
Those fuselage sets pre-date the Airfix 727-200 kit - they were to convert the Airfix 727-100 kit into a -200.
Airfix ended up permanently modifiying their -100 moulds to make their own -200 kit, thus why no more Airfix -100 releases.
BTW,
If you want to convert an Airfix -200 back to a -100, Ozmods have a conversion fuselage (mastered from an original -100 kit) here: http://www.ozmods-kits.com/conversions-upgrades-accessories-1144 (Scroll halfway down)
Or there's always the Revell -100 kit that's still available...
Cheers!