> Typically, a clean-room design is done by having someone examine the system to be reimplemented and having this person write a specification. This specification is then reviewed by a lawyer to ensure that no copyrighted material is included. The specification is then implemented by a team with no connection to the original examiners.

https://en.wikipedia.org/wiki/Clean_room_design

yes, reading that description it seems pretty clear to me that they did not read the code but they had access to the working system and then

>by reverse engineering and then recreating it without infringing any of the copyrights associated with the original design.

reverse engineering is not 'reading the code'.