Update, Nov. 6: Boeing said the Wedgetail will be assembled in Renton, as it has in the past. Discussions are underway with the UK to perform final modifications there (similar to how KC-46A tankers move from final assembly to the Everett Modification Center for installation of military equipment). However, no agreement has been reached yet.
Nov. 5, 2018, © Leeham News: A UK defense publication reported late today (US time) that Boeing agreed to final assembly of the 737-based Wedgetail radar and surveillance airplane in the UK.
This marks the first time a 7-Series commercial-based airplane will be assembled outside the US.
The 737 finishing center in China, which opens this year, installs interiors and paints the airplane of finished 737s.
If the report is confirmed by Boeing, this marks a huge strategic and psychological step in how Boeing Commercial Airplanes approaches final assembly in the future.