What is the base movement for the IWC Portuguese Grande Complication?

Hi all,

I was leafing through a copy of Wristwatch Annual 2012 by Abbeville Press when I came across something that I found rather striking in the IWC section.

Whenever a watch movement uses an ETA or other generic movement as a base, there is an indication in the specifications section. They indicate that the Portuguese Grand Complication is based on the Valjoux 7750 movement. Is this accurate?

I was less surprised to find this in some of the Aquatimers, also a Sellita S200 in a Portofino.

If this is the case, will IWC be shifting to an in-house caliber for future Grande Complications? I must be hard to position a GC based on a generic movement. I can imagine IWC having to use a Sellita SW500 in the future given ETA's constriction of supply to third parties. Somehow "Sellita" and "Grand Complication" don't seem to match...

Are there other watch companies basing their Grande Complication on generic movements?

Phil --this is discussed in the archives. When IWC introduced the grand comp, there were very few automatic chrono movements available nor made by third parties (even Patek used a Lemania). The Valjoux 7750 was basically stripped so only a fraction --I'm guessing 60 out of 200+ parts remainded. The exact numbers are in the archives. So the design of the base is not original, but it's scarcely a generic movement.

Thank you Michael, and duly noted concerning checking the archive before embarking on questions that may already have answers.