Hello!
The answer is mostly yes. Before 3D airports were released, we used a software called WED (also used for building airports in X-Plane) which saw the 2D layouts of thousands of airports.
All airports were automatically generated at first, although these mostly exist now in smaller airports, usually consisting of just a runway, or runway and paralell taxiway/pavement. The majority of these, especially all the larger airports were edited manually over time. Whilst I don’t have the exact number of airports that were edited during this time, there were almost 20,000 contributions into the Github database of airports between February 2016, and October 2021.
The layouts often looked like this, and can be seen in older ThirdParty and Scenery Editing topics.
Nowadays we manually edit all 2D and 3D airports that are released each update in-app. Currently, there are over 1,000 released 3D airports, all manually edited by members of the community. You can find out more about how the team edits airports, and how you can join below. :)