I am just reminded, and it's probably in the book, that one of the factors behind the rapid evacuation was there was a complete relief crew, in uniform, on board deadheading out to Zurich to bring another BOAC aircraft back, and who obviously doubled up the crew able to assist.
JT3D-3 powered -336s ....... the initial three came as freighters, but with a complete set of passenger cabin windows. Hmm ...
The cargo door 707320C became the default aircraft model, with windows giving a fully convertible aircraft. Many went to cargo use in later years. It was a fraction more costly due to the extra weight and purchase price of the door, but for passenger airlines in the US there was a subsidy paid by the US government to airlines who committed their fleets to possible emergency use by the military, for which the cargo door was required. This standard configuration spread out across other carriers as well, and in the end was justified in the final secondhand price, as by the late 1970s cargo-or-passenger 707s were still in demand whereas passenger-only ones became unsaleable.
Some airlines left the windows in, others installed quite-obvious plugs (which may just have been covers), and others did a proper job with plugs fully painted over.